Expression of epithelial and neural antigens in small cell and non small cell lung carcinoma

Seventy-one lung carcinomas from 66 different patients were stained with a panel of monoclonal antibodies. Twenty-nine were small cell lung carcinoma (SCLC), 15 adenocarcinomas, 17 squamous carcinomas and 10 large cell carcinomas. Three of the monoclonal antibodies recognize different cytokeratins, three recognize other epithelial antigens and one recognizes a neural antigen. Both formalin-fixed and cryopreserved tumours were studied using an indirect immunoperoxidase method. 23/29 SCLC reacted with all but one of the antibodies which recognize epithelial antigens. This staining was similar to that seen in non small cell lung carcinomas (NSCLC) and provides further evidence that SCLC are true epithelial tumours. All but one of the SCLC stained with the antibody recognizing a neural antigen. This antibody did not stain squamous or adenocarcinomas. However, four of the large cell carcinomas stained well with this antibody, suggesting that SCLC and some large cell carcinomas share a common pathway of differentiation. There were variations of staining seen both within and between tumours. This has obvious implications if immunotargetting with monoclonal antibodies is to be used diagnostically or therapeutically.     

P63 expression in lung carcinoma: a tissue microarray study of 408 cases.

p63 is a recently discovered member of the p53 family that has been shown to be important in the development of epithelial tissues. p63 may also play a role in squamous cell carcinomas of the lung, head and neck, and cervix, and its expression is increased in these tumors. The purpose of this study was to investigate the expression of p63 in a broad spectrum of histologic types of lung tumors. A total of 441 cases of primary lung tumors with follow-up data were identified, and the paraffin-embedded tissue blocks were used to construct a duplicate core tissue microarray. After review of the tissue cores, 408 cases, consisting of 123 squamous cell carcinomas, 93 adenocarcinomas, 68 large cell carcinomas, 68 classic carcinoids, 31 atypical carcinoids, 11 large cell neuroendocrine carcinomas, and 14 small cell carcinomas, were adequate for analysis. Immunohistochemistry was performed at 2 different laboratories using monoclonal antibody 4A4 to detect the expression of p63, using different staining protocols. p53 expression was also studied with immunohistochemistry using monoclonal antibody DO-7. Kaplan-Meier curves were plotted to compare the survival of p63-expressing versus nonexpressing tumors. A large proportion of squamous cell carcinomas expressed p63 (96.9%), most showing strong positive nuclear immunoreactivity. Expression in other nonsmall cell lung cancers was also present. Thirty percent of adenocarcinomas and 37% of large cell carcinomas showed p63 expression. In the neuroendocrine tumors, an increasing proportion of tumors stained for p63 as tumor grade increased; 1.9% of classic carcinoids, 30.8% of atypical carcinoids, 50% of large cell neuroendocrine carcinomas, and 76.9% of small cell carcinomas were positive. Approximately half of the positively staining neuroendocrine cases showed strong staining. Expression of p63 was of prognostic significance in neuroendocrine tumors (P < 0.0001), with higher-grade tumors more likely to express p63. Correlation between p63 and p53 expression was not observed (P = 0.18) in nonsmall cell lung cancer; however, a significant correlation between the 2 markers was found in neuroendocrine tumors (P < 0.0001). p63 staining was repeated with a different staining protocol, yielding similar results overall but a lower percentage of positive cases (34.2% vs. 48.4% of tumors positive). In conclusion, p63 expression is consistently expressed in squamous cell carcinoma in the lung, but is also expressed in a subset of adenocarcinomas and large cell carcinomas. Pulmonary neuroendocrine tumors also show p63 staining in some instances, particularly in higher-grade tumors, and the majority of small cell carcinomas are p63-positive. These results suggest that p63 may be involved in oncogenesis in a broader range of tumors than was previously thought.     

Bcl-2 protein expression in lung cancer and close correlation with neuroendocrine differentiation.

For determination of the cellular distribution of bcl-2 expression in lung cancer and clarification of its correlation with cell neuroendocrine differentiation, Bcl-2 immunostaining was carried out on a large series of formalin-fixed, paraffin-embedded lung cancer samples, and four general neuroendocrine marker and seven peptide hormone stainings were carried out on all Bcl-2-positive squamous cell carcinomas and adenocarcinomas of the lung as well as on 8 pulmonary neuroendocrine carcinomas histologically diagnosed. In addition, 3 small cell lung cancer cell lines were studied by Western blotting. Neuroendocrine differentiation in Bcl-2-negative squamous cell carcinomas and adenocarcinomas was examined with chromogranin A and alpha-subunit of Go protein stainings. Bcl-2 protein was detected in 104/111 small cell carcinomas, 8/8 neuroendocrine carcinomas, 0/6 typical (well differentiated) carcinoids, 23/64 squamous cell carcinomas, 4/65 adenocarcinomas, and all 3 small cell lung cancer cell lines. All 8 neuroendocrine carcinomas, 11 of the Bcl-2-positive squamous cell carcinomas, and all 4 Bcl-2 positive adenocarcinomas expressed multiple neuroendocrine markers. The distributions of Bcl-2 and neuroendocrine marker immunoreactivity closely paralleled each other on consecutive sections. In squamous cell carcinomas, Bcl-2-positive cells could be roughly subdivided into those with neuroendocrine differentiation features, usually demonstrating intense Bcl-2 staining, with basaloid tumor cells usually expressing weak to moderate Bcl-2 staining. The present study clearly shows Bcl-2 protein expression to be remarkably differentially regulated according to histological types of lung cancers and to appear to quite likely be closely associated with neuroendocrine differentiation of tumor cells, indicating that bcl-2 is importantly involved in cell development and differentiation, in addition to protecting cells from apoptosis. Bcl-2 might be usable as a neuroendocrine marker in lung cancers and possibly also in neural-crest-derived tumors.     

Histidine decarboxylase expression as a new sensitive and specific marker for small cell lung carcinoma.

Histidine decarboxylase is one of the enzymes of the amine precursor uptake and decarboxylation system and is known to be distributed in mast cells and enterochromaffin-like cells. With the hypothesis that histidine decarboxylase expression is a marker for neuroendocrine differentiation, we studied the immunoreactivity of histidine decarboxylase in neuroendocrine cells and tumors of the thyroid gland, adrenal medulla, lung, and gastrointestinal tract. Formalin-fixed paraffin sections were subjected to immunohistochemistry using anti-histidine decarboxylase antibody, and the sensitivity and specificity were compared with those of conventional neuroendocrine markers (CD56, chromogranin A, synaptophysin, and neuron-specific enolase). Enterochromaffin or enterochromaffin-like cells, adrenal chromaffin cells, and thyroid C-cells were positive for histidine decarboxylase, and related tumors (carcinoid tumor, pheochromocytoma, medullary carcinoma) showed a high percentage of positive staining. Furthermore, we used the antibody to distinguish small cell lung carcinoma from non-neuroendocrine lung carcinoma and also to detect neuroendocrine differentiation in large-cell neuroendocrine carcinoma and gastrointestinal small-cell carcinoma. The anti-histidine decarboxylase antibody stained most small cell lung carcinoma (18 of 23, sensitivity 0.78), and was rarely reactive with non-neuroendocrine lung tumors (2 of 44; specificity, 0.95). These values were close to those obtained from CD56 staining (sensitivity/specificity, 0.87/0.98). Histidine decarboxylase was also positive for 6 of 12 large cell neuroendocrine carcinomas and 4 of 7 gastrointestinal small cell carcinomas. In conclusion, we demonstrated that histidine decarboxylase is useful to distinguish between small cell lung carcinoma and non-neuroendocrine carcinoma and to demonstrate neuroendocrine differentiation.     

CD44 expression is a feature of prostatic small cell carcinoma and distinguishes it from its mimickers

Small cell neuroendocrine carcinoma of the prostate is a rare variant of prostatic cancer that shares morphologic similarity with prostatic adenocarcinoma of Gleason 5 pattern. It has also been considered morphologically and immunohistochemically indistinguishable from small cell neuroendocrine carcinomas of other origins. CD44 is a cell-surface molecule proposed to identify cancer stem/progenitor cells in prostate cancer. We performed immunohistochemical study for CD44 expression in 11 cases of prostatic small cell neuroendocrine carcinoma and compared its patterns of expression with 73 cases of prostatic adenocarcinoma and 47 cases of small cell neuroendocrine carcinomas of other organs. Strong and diffuse membrane staining for CD44 was observed in 100% of the prostatic small cell neuroendocrine carcinomas. In conventional adenocarcinomas of the prostate, positive staining was only seen in rare, scattered tumor cells; and CD44 staining was negative in most of the small cell neuroendocrine carcinomas of nonprostate origin. The difference in CD44 expression between small cell neuroendocrine carcinomas of the prostate and those of other organs are statistically significant (P < .001). Our study demonstrates the utility of immunohistochemical staining for CD44 in distinguishing prostatic small cell neuroendocrine carcinoma from its mimickers including prostatic adenocarcinoma of Gleason 5 pattern and small cell neuroendocrine carcinomas of other organs. CD44 is the first marker that shows a high degree of tissue/organ specificity for small cell neuroendocrine carcinomas. Because CD44 is a putative marker of prostate cancer stem cells, the strong and diffuse expression of CD44 and the lack of expression of prostate luminal differentiation markers androgen receptor and prostatic specific antigen in prostatic small cell neuroendocrine carcinomas suggest that the tumor cells may retain cancer stem cell features.     

E-cadherin nuclear staining is useful for the diagnosis of ovarian adult granulosa cell tumor

We recently have demonstrated nuclear localization of E-cadherin in ovarian adult granulosa cell tumors (Histopathology 2011;58:423). The purpose of the present study is to investigate the diagnostic utility of E-cadherin nuclear staining for the differential diagnosis between ovarian adult granulosa cell tumor and its morphological mimics. Tissue samples taken from 81 ovarian tumors and 20 extraovarian tumors were immunohistochemically stained using monoclonal anti-E-cadherin antibody recognizing cytoplasmic domain (clone 36 supplied by BD Biosciences, San Jose, CA). The ovarian tumors consisted of 30 adult granulosa cell tumors, 3 Sertoli-stromal cell tumors, 14 fibrothecomas, 5 carcinoid tumors, 1 large cell neuroendocrine carcinoma, 18 endometrioid adenocarcinomas, and 10 poorly differentiated serous adenocarcinomas. Extraovarian tumors consisted of 16 uterine endometrial stromal neoplasms and 4 pulmonary small cell carcinomas. Only tumor cells with nuclear staining were considered positive in this study. Ninety percent of adult granulosa cell tumors, 67% of Sertoli-stromal cell tumors, 64% of fibrothecomas, 75% of endometrial stromal neoplasms, 75% of small cell carcinomas, and the one large cell neuroendocrine carcinoma showed E-cadherin nuclear expression, whereas all the ovarian carcinoid tumors, endometrioid adenocarcinomas, and poorly differentiated serous adenocarcinomas were negative. E-cadherin nuclear staining is useful in distinguishing between adult granulosa cell tumors and ovarian adenocarcinomas or carcinoid tumors. However, it is of limited use for distinguishing between adult granulosa cell tumors and endometrial stromal neoplasms or small cell carcinomas. E-cadherin should be included in the immunohistochemical panel for an accurate diagnosis of ovarian adult granulosa cell tumors.     

Evaluation of CD43 expression in non-hematopoietic malignancies

ObjectivesCD43 is normally expressed only on the surface of leukocytes, and is considered a sensitive and specific marker for hematologic malignancies. As such, it may have diagnostic utility in confirming hematolymphoid lineage in cases that are negative for CD45. Aberrant CD43 expression has been described in non-hematopoietic tumors, although literature data on this topic is variable and sometimes contradictory. To clarify and expand on existing literature findings, we evaluated CD43 expression by immunohistochemistry (IHC) in a large cohort (307) of non-hematopoietic neoplasms, including poorly differentiated malignancies.Methods17 tissue microarrays and sections from 19 individual cases were stained with CD43 (clone DF-T1) monoclonal antibody. The proportion of positive cells, stain localization (nuclear, cytoplasmic or membranous), and intensity (compared to internal leukocyte controls) were recorded in all cases.ResultsThere were 98/307 (32%) positive cases, that showed focal weak nuclear staining in 1–25% of cells, including 23/25 (92%) pancreatic ductal adenocarcinomas; 31/34 (91%) breast invasive ductal carcinomas; 13/15 (87%) papillary thyroid carcinomas; 3/4 (75%) follicular thyroid carcinomas; 6/15 (40%) renal cell carcinomas; 9/28 (32%) lung adenocarcinomas; 1/13 (8%) lung squamous cell carcinomas (SCCs); 2/8 (25%) prostate adenocarcinomas; 8/62 (13%) colon adenocarcinomas; and 2/21 (10%) neuroendocrine neoplasms. None of the positive cases demonstrated strong, membranous CD43 expression comparable to that seen in background mature lymphocytes or segmented neutrophils. Negative cases included 11 cervical SCCs, 12 cervical adenocarcinomas, 19 urothelial carcinomas, 10 lung small cell carcinomas, 11 sarcomas, and 19 poorly differentiated carcinomas from various tissue sites.ConclusionsIn our cohort, most non-hematopoietic neoplasms are negative for CD43 expression, with a subset showing focal, weak nuclear positivity. This data indicates that uniform and strong membranous staining appears to be specific to hematopoietic neoplasms.     

P63 in pulmonary epithelium,pulmonary squamous neoplasms,and other pulmonary tumors

p63 is a p53-homologous nuclear protein that appears to play a crucial role in regulation of stem cell commitment in squamous and other epithelia. In this study, p63 expression was examined in benign lung and in neoplasms of pulmonary origin. Eighty sections from routinely fixed and processed archival bronchoscopic biopsy or lobectomy specimens were pretreated with citric acid (pH 6.0) for antigen retrieval, then incubated overnight with anti-p63 monoclonal antibody 4A4. Slides were stained using a streptavidin-biotin kit and diaminobenzidine as chromagen, and were counterstained with hematoxylin. In normal lung, p63 intensely stained nuclei of bronchial reserve cells but did not stain ciliated cells, alveolar epithelial cells, or nonepithelial cells. The lower strata of squamous metaplastic bronchial epithelium stained positively. All squamous-cell carcinomas stained positively (n = 30). In some well-differentiated carcinomas, staining was found at the periphery of tumor nests but was negative in central zones showing squamous maturation. Poorly differentiated carcinomas showed very high proportions (80% to 100%) of p63-positive nuclei. All small-cell carcinomas were p63 negative (n = 9). Staining of bronchioloalveolar carcinomas (n = 7) and adenocarcinomas (n = 23) was variable: some tumors showed no detectable staining, others showed heterogeneously positive staining. Adenosquamous carcinomas (n = 5) displayed a unique basalar staining pattern. Carcinoid tumors were almost entirely negative (n = 5). We conclude that p63 is expressed in benign bronchial stem cells, in neoplastic cells with either squamous differentiation or squamous differentiating potential, and in a subpopulation of adenocarcinomas. p63 immunostaining may also aid in some histopathologic distinctions, such as in small biopsies where the differential diagnosis is poorly differentiated squamous carcinoma versus small-cell carcinoma. A stem cell biology-based classification system for squamous carcinomas is proposed.     

High-level expression of CD109 is frequently detected in lung squamous cell carcinomas

CD109 is a glycosylphosphatidylinositol (GPI)-anchored cell surface protein, which is a member of the alpha2-macroglobulin/C3, C4, C5 family of thioester-containing proteins. It has been reported that CD109 is expressed in a subset of hematopoietic cells, endothelial cells and several kinds of human tumors. Herein it is reported that the CD109 protein is preferentially expressed in lung squamous cell carcinomas compared with other types of lung carcinoma including adenocarcinomas, large cell carcinomas and small cell carcinomas. Immunohistochemical staining of surgically resected lung specimens using an anti-CD109 antibody detected CD109 expression in basal cells of bronchial and bronchiolar epithelia and myoepithelial cells of bronchial secretary glands, but not in bronchial and bronchiolar apical epithelial cells and alveolar epithelial cells. Furthermore, the CD109 immunoreactivity was observed in squamous cell carcinomas at a high frequency compared with other types of lung carcinoma. Although the detailed function of CD109 protein is unclear, these results suggest that CD109 expression may play a role in the development of lung squamous cell carcinoma.     

Neuroendocrine differentiation in cervical carcinoma.

AIMS: To examine neuroendocrine differentiation, as shown by chromogranin A (CGA) expression, in cervical carcinomas. METHODS: Sixty seven cervical carcinomas were studied and were classified as adenocarcinomas, adenosquamous carcinomas or squamous cell carcinomas based on the assessment of haematoxylin and eosin staining and stains for mucin. Where features of glandular differentiation were identified, sections were also stained for evidence of intestinal type mucin. CGA immunostaining was done and the results were graded on a three point scale: 0, + (1-5% of cells positive) and ++ (> 5% of cells positive). These findings were then analysed with respect to lymph node status, tumour differentiation and clinical outcome. RESULTS: There were 32 adenocarcinomas, 18 adenosquamous carcinomas and 17 squamous cell carcinomas. Positive staining was seen in 14 (20.9%) cases, of which four were strongly positive. All but one case were either adenocarcinomas or adenosquamous carcinomas. There was a trend for CGA positivity to be related to intestinal differentiation but this failed to reach statistical significance. No correlation could be demonstrated between CGA staining and lymph node status, tumour differentiation and clinical outcome. CONCLUSIONS: Neuroendocrine differentiation is common in cervical carcinomas where there is evidence of glandular differentiation. Whilst the numbers in this study are relatively small, the presence of neuroendocrine cells in otherwise typical carcinomas does not seem to have any association with clinical behaviour.     

Expression of novel neuroendocrine marker insulinoma-associated protein 1 (INSM1) in genitourinary high-grade neuroendocrine carcinomas: An immunohistochemical study with specificity analysis and comparison to chromogranin,synaptophysin, and CD56

Confirmation of genitourinary high-grade neuroendocrine carcinomas (GU-HGNECs) often requires immunohistochemical staining. Here we evaluated a novel neuroendocrine marker, insulinoma-associated protein 1 (INSM1), in GU-HGNECs with comparison to chromogranin, synaptophysin and CD56. Immunohistochemical expression of INSM1, chromogranin, synaptophysin, and CD56 was evaluated in 39 GU-HGNECs using full tissue sections [4 in kidney, 28 in urinary bladder, and 7 in prostate; 31 small cell carcinomas (SmCCs), 6 large cell neuroendocrine carcinomas (LCNECs), 2 mixed SmCC-LCNECs]. In 33 SmCCs/components, INSM1 showed similar sensitivity (93.9 %) to chromogranin (87.8 %), synaptophysin (93.9 %) and CD56 (87.8 %), and stained a similar percentage of tumor cells (52 %) to chromogranin (49 %) and CD56 (52 %), but lower than synaptophysin (87 %) (p < 0.0001). In 8 LCNECs/components, INSM1 is similar to chromogranin, synaptophysin or CD56 in sensitivity (62.5 %, 62.5 %, 75 %, 62.5 %, respectively) and the mean percentage of positively stained tumor cells (21 %, 44 %, 48 %, 37 %, respectively). INSM1 is more sensitive for SmCCs than LCNECs (93.9 % vs. 62.5 %, p = 0.015). INSM1 showed 97.4 % specificity upon analyzing 273 genitourinary non-neuroendocrine tumors on tissue microarrays. Our study indicates that INSM1 is a sensitive marker for genitourinary HGNECs with high specificity. For genitourinary SmCCs, INSM1 shows similar sensitivity to chromogranin, synaptophysin and CD56 but stains a lower percentage of tumor cells than synaptophysin. For genitourinary LCNECs, INSM1 showed similar sensitivity to chromogranin, synaptophysin and CD56. INSM1 is more sensitive for genitourinary SmCCs than LCNECs. Our result and literature review indicate that whether INSM1 is more sensitive than conventional neuroendocrine markers for HGNECs depends on the tumor primary sites.     

Protein 1 and Clara cell 10-kDa protein distribution in normal and neoplastic tissues with emphasis on the respiratory system

Thirty-six different normal tissues and 13 different malignant epithelial tumours, were examined immunohistochemically for the presence of protein 1 (P1) and Clara cell 10-kDa protein (CC10). Adenocarcinomas of the lung were also examined for the expression of pulmonary surfactant apoprotein using a monoclonal antibody (PE-10). The staining results of P1 and CC10 were almost identical both in normal tissues and in malignant tumours. In normal lung, Clara cells were strongly positive for both P1 and CC10. In addition, some goblet cells and non-ciliated non-mucus cells in the upper airways were moderately positive for both proteins. In the malignant tumours, some lung cancers were positive for P1 and CC10, both of which were positive in the same tumour cells on sequential sections. In 117 lung cancers, P1 and CC10 were positive in 10.2% of adenocarcinomas, 20.5% of squamous cell carcinomas, and 12.5% of large cell carcinomas. PE-10 stained positively in 65.3% of adenocarcinomas, a frequency significantly higher than that of P1 and CC10 (P<0.01). These results suggest that P1 and CC10 are nearly identical proteins, that both are useful markers of Clara cells, and that many pulmonary adenocarcinomas express surfactant apoprotein rather than Clara cell proteins.     

Immunoperoxidase staining for Ia-like antigens in paraffin-embedded tissues from human melanoma and lung carcinoma.

The human Ia-like antigens that are predominantly expressed by cells associated with immunologic function has been considered as a diagnostic marker of malignant transformation of some nonlymphoid tissues. Immunoperoxidase staining of formalin-fixed and paraffin-embedded tissue sections with a monoclonal antibody to Ia-like antigens was chosen for assessment of the value of this marker for diagnosis in surgical pathology. Monoclonal antibody LK8D3 developed against a human melanoma cell line bearing Ia-like antigens was found to react in serologic and immunochemical studies with an antigenic determinant of Ia-like antigens that was relatively stable to formalin fixation and paraffin embedding. Avidin-biotin complex peroxidase staining of formalin-paraffin sections with LK8D3 showed focal expression of Ia-like antigens in 3 of 12 melanomas, whereas all 8 cases of intradermal nevi were negative. Immunoperoxidase staining of formalin-paraffin sections of lung carcinomas with antibody LK8D3 was related to the histologic subtype of tumors. Thus, squamous cell carcinomas showed only very focal staining for Ia-like antigens in 5/9 cases, while widespread and intense Ia-like immunoreactivity was seen in 3/5 cases of lung adenocarcinomas, including two bronchioalveolar carcinomas. The presence of Ia-like antigens in lung adenocarcinoma may not be entirely associated with malignant transformation, because normal alveolar lining cells were stained with the antibody.     

Differential distribution of the neuron-associated class III beta-tubulin in neuroendocrine lung tumors

OBJECTIVE: To study the immunoreactivity profile of the neuron-associated class III beta-tubulin isotype (beta III) in epithelial lung tumors. DESIGN: One hundred four formalin-fixed, paraffin-embedded primary and metastatic lung cancer specimens were immunostained with an anti-beta III mouse monoclonal antibody (TuJ1) and an anti-beta III affinity-purified rabbit antiserum. Paraffin sections from fetal, infantile, and adult nonneoplastic lung tissues were also examined. RESULTS: In the fetal airway epithelium, beta III staining is detected transiently in rare Kulchitsky-like cells from lung tissues corresponding to the pseudoglandular and canalicular but not the saccular or alveolar stages of development. beta III is absent in healthy, hyperplastic, metaplastic, and dysplastic airway epithelium of the adult lung. In contrast, beta III is highly expressed in small cell lung cancer, large cell neuroendocrine carcinoma, and in some non-small cell lung cancers, particularly adenocarcinomas. There is no correlation between expression of beta III and generic neuroendocrine markers, such as chromogranin A and/or synaptophysin, in pulmonary adenocarcinomas. Also, focal beta III staining is present in primary and metastatic adenocarcinomas (to the lung) originating in the colon, prostate, and ovary. beta III is expressed to a much lesser extent in atypical carcinoids and is rarely detectable in typical carcinoids and squamous cell carcinomas of the lung. The distribution of beta III in small cell lung cancer and adenocarcinoma metastases to regional lymph nodes and brain approaches 100% of tumor cells, which is substantially greater than in the primary tumors. CONCLUSIONS: In the context of neuroendocrine lung tumors, beta III immunoreactivity is a molecular signature of high-grade malignant neoplasms (small cell lung cancer and large cell neuroendocrine carcinoma) although its importance in atypical carcinoids must be evaluated further. In addition, beta III may be a useful diagnostic marker in distinguishing between small cell lung cancers and certain non-small cell lung cancers (poorly differentiated squamous cell carcinomas), especially in small biopsy specimens. To our knowledge, beta III is the only tumor biomarker that exhibits a substantially more widespread distribution in poorly differentiated than in better differentiated pulmonary neuroendocrine tumors. However, the significance of beta III phenotypes in non-small cell lung cancer, particularly adenocarcinoma, with respect to neuroendocrine differentiation and prognostic value, requires further evaluation.     

NCAM (neural cell adhesion molecules) expression in malignant mesotheliomas

Neural cell adhesion molecules (NCAM) are adhesion molecules expressed by neural and neuroendocrine tumors and a few biphasic tumors such as synovialosarcomas and breast phyllode tumors. To investigate NCAM expression in mesotheliomas, we studied 26 cases of epithelioid (n = 12), biphasic (n = 11), and sarcomatoid (n = 3) malignant mesotheliomas (MM), in comparison with normal mesothelium, and 50 primary non-small cell lung carcinomas (NSCLC) (25 adenocarcinomas [ADC] and 25 squamous cell carcinomas [SCC]), using electron microscopy as a gold standard for recognition of MM. NCAM reactivity using 123C3 antibody was compared with that of NE markers such as chromogranin A and synaptophysin. Although normal mesothelium remains negative, NCAM was expressed in 19 of 26 MM (73%) with a membranous staining on frozen or paraffin sections. In 6 of 12 epithelioid MM, the tumor cells expressed NCAM, whereas in 5 cases stromal fibroblasts showed a strong but focal staining. In 11 biphasic MM, 4 presented an NCAM reactivity of both epithelioid and spindle cell components, whereas in 7, only fusiform component was NCAM positive. Two of 3 sarcomatoid MM showed an NCAM expression. Chromogranin expression was never seen, whereas synaptophysin was noticed in 2 cases. No case of NSCLC showed membranous 123C3 staining, whereas 2 ADC weakly expressed synaptophysin. We conclude that NCAM expression in MM is reminiscent of its expression in mesoderm during fetal life and consistent with that reported in other biphasic tumors. These data show that NCAM expression occurs in 73% of MM, highly exceeding that observed in lung cancer.     

Pathological study of carbohydrate antigens in human lung cancer with monoclonal antibodies]

The expressions of carbohydrate antigens were examined with panel of specific anti-carbohydrate monoclonal antibodies (MAbs) on human lung cancer tissues. The MAbs used were SH1, SH2, SNH3, AH6, CA3F4, TKH2, TKH6 and TKH5 which define Lex, dimeric Lex, sialosyl Lex, Ley, Lea, sialosyl Tn, Tn and fucosyl GM1, respectively. Paraffin-embedded tissue sections (30 squamous cell carcinomas, 30 adenocarcinomas and 27 small cell carcinomas) were tested by immunohistological staining. Evaluation of stained specimens was performed by taking mean value of scores evaluated by three independent examiners. In squamous cell carcinoma, expression of Ley, sialosyl Tn, sialosyl Lex and Lea was significantly higher than other antigens. Lex was also expressed especially in keratinized tissues. In adenocarcinoma, Lea was expressed most remarkably. Sialosyl Lex, Ley, sialosyl Tn were also highly expressed in malignant cells. There was no significant difference in staining patterns between well and poorly differentiated adenocarcinomas. Sialosyl Tn and sialosyl Lex were positive in morphologically normal mucous glands adjacent to tumors. In small cell carcinomas, Ley was expressed more than other types of tumors, whereas Lex and sialosyl Tn were less than others. Tn antigen was observed throughout adenocarcinomas, squamous and small cell carcinomas in a relatively weak manner. Dimeric Lex and fucosyl GM1 antigens were not detected. Most of normal lung sections showed negative staining with those MAbs. These findings indicate that there are differential expressions of certain carbohydrate antigens in different types of human lung cancers based on their origins.     

Neuroendocrine differentiation in poorly differentiated lung carcinomas: a light microscopic and immunohistologic study

Frozen, unfixed tissue sections from 56 poorly differentiated, non-small cell primary lung tumors were examined by the immunoperoxidase technique with a panel of monoclonal antibodies to neuroendocrine (chromogranin A (CGA), synaptophysin (SYN), S-100) and intermediate filament (cytokeratin, vimentin, neurofilament) antigens. Although light microscopic features of neuroendocrine (NE) differentiation were not present, staining for CGA and/or SYN was identified in 5/17 (29%) large cell carcinomas (LCC) and 4/19 (21%) poorly differentiated adenocarcinomas (PDA). Diffuse, strong SYN staining was present in two LCC and one PDA. Heterogeneous intermediate filament expression (vimentin and/or neurofilament) was frequent (LCC, 10/17 (59%); PDA, 10/19 (53%)) and accompanied NE markers in 8/9 (89%) cases. Poorly differentiated squamous carcinomas were more homogeneous, with focal SYN in only 1/20 (5%) and focal presence of intermediate filaments other than cytokeratin in only 2/20 (10%). We conclude: (a) immunohistologic evidence of NE differentiation is present in a significant proportion of pulmonary large cell and poorly differentiated adenocarcinomas and rare in poorly differentiated squamous carcinomas; (b) NE differentiation is generally accompanied by heterogeneous intermediate filament expression; (c) divergent NE differentiation is not necessarily reflected by light microscopic features.     

A 22-kd surface antigen detected by monoclonal antibody E 48 is exclusively expressed in stratified squamous and transitional epithelia.

After immunization of mice with viable cells of a metastasis of a laryngeal squamous cell carcinoma, a monoclonal antibody E 48 was obtained that detects an epitope present exclusively in squamous and transitional epithelium and their neoplastic counterparts. Immunoblotting revealed that E 48 recognizes a 22 kd molecule. Seventy-five of 76 squamous cell carcinomas from the head and neck, lung, cervix, and skin stained positively, whereas various adenocarcinomas from the colon, lung, and breast, and small cell lung carcinomas consistently stained negatively. The E 48 antigen, which is formaldehyde resistant, appears to be a reliable marker for differentiation of squamous cell carcinomas from adenocarcinoma, and small cell carcinomas.     

The frequency of neuroendocrine cell hyperplasia in patients with pulmonary neuroendocrine tumours and non-neuroendocrine cell carcinomas

Aims:  To evaluate the frequency of neuroendocrine cell hyperplasia (NEH) in resected neuroendocrine tumours and non-neuroendocrine cell carcinomas and to study its relationship to selected clinical parameters.
Methods and results:  Random blocks without tumour from resected typical carcinoids (TCs, n  = 46), atypical carcinoids (ACs, n  = 14), large cell neuroendocrine carcinomas (LCNECs, n  = 18), small cell carcinomas (SCLCs, n  = 22), adenocarcinomas (ADENOs, n  = 26) and squamous cell carcinomas (SCCs, n  = 18) were stained for CD56 and evaluated for linear proliferations, cell aggregates (>4 CD56+ cells), and tumourlets (<5 mm with basement membrane invasion). There was a statistically significant difference between the frequency of NEH in all neuroendocrine tumours (TC/AC/LCNEC/SCLC, 35/100, 35%) ( P  = 0.009) when compared with non-neuroendocrine carcinomas (ADENO/SCC, 6/44, 14%) and in the frequency of NEH in TC (21/46, 46%) versus all other tumours (AC/LCNEC/SCLC/SCC/ADENO, 20/98, 20%) ( P  = 0.001). There was increased frequency of NEH in peripheral TCs (8/13, 62%) compared with central TCs (14/33, 43%) ( P  = 0.33). There was no association between smoking history and NEH. Clinical and imaging data showed no evidence of an increased frequency of obliterative bronchiolitis in patients with NEH.
Conclusions:  NEH is significantly increased in the background lung of neuroendocrine tumours when compared with non-neuroendocrine carcinomas, supportive data for NEH having neoplastic potential.     

Cytokeratins and lung carcinomas

BACKGROUND: Recently, cytokeratins (CK) were studied as tumor markers for many carcinomas. In lung cancer they appeared to be useful in distinguishing primary from secondary tumors, in histological typing as well as in evaluating patient's prognosis. However, the results have yet to be conclusive. In this study, expression of CK7, CK10/13, CK18, CK19, CK20 was investigated in a group of 72 surgically resected specimens of lung including 31 adenocarcinomas, 30 squamous cell carcinomas and 11 neuroendocrine carcinomas. Cytokeratin immunophenotypes were analyzed in comparison to histological characteristics of tumors, TNM stages and patients survival. RESULTS: CK7, CK10/13 and CK18 can be used in distinguishing the lung adenocarcinomas from the lung squamous cell carcinomas: CK7(+), CK10/13(-), CK18(+) for adenocarcinomas; CK7(-), CK10/13(+), CK18(-) for squamous cell carcinomas. Relatively higher CK7 and CK18 immunostaining rates of the squamous cell carcinomas with high keratinization, with high percentage of dead cells and with late stages of disease suggested their prognostic significance but it was not confirmed when comparing different survival groups. Both adenocarcinomas and squamous cell carcinomas were stained strongly with antibody against CK19 (90.3% and 86.7% respectively) but much less with anti-CK20 antibody (9.7% and 3.3% respectively). In general, neuroendocrine tumors of the lung were non-reactive for these cytokeratins except CK18, among them all carcinoid tumors expressed CK18 abundantly.