Characteristics of loss of heterozygosity in large cell neuroendocrine carcinomas of the lung and small cell lung carcinomas

Large cell neuroendocrine carcinoma (LCNEC) of the lung is a new entity. Besides morphological characteristics, its molecular biological features have been investigated by many researchers and compared to those of other neuroendocrine carcinomas, small cell lung carcinoma (SCLC) and carcinoid tumor (CT). However, there are few reports that show the significantly different genetic characteristics between them. The purpose of the present paper was to study the frequency of loss of heterozygosity (LOH) at chromosome 3p (3p14.2) in 38 neuroendocrine carcinomas of the lung (13 LCNEC, 11 SCLC and 14 CT) and 10 large cell carcinomas (LCC). The frequencies of LOH at 3p14.2 were 69.2% in LCNEC, 81.8% in SCLC, 50.0% in LCC and 7.14% in CT. Those at 22q13.3 were 30.8% in LCNEC, 72.7% in SCLC, 45.5% in LCC and 7.14% in CT. In particular, the frequency of SCLC with LOH at both 3p14.2 and 22q13.3 (63.6%) was significantly higher than that of LCNEC (15.4%). LCNEC and SCLC had different characteristics of LOH patterns at 3p14.2 and 22q13.3. The combined analysis of the LOH at 3p14.2 and 22q13.3 is thought to be useful for differential diagnosis between LCNEC and SCLC.     

High-grade neuroendocrine carcinoma of the lung: Comparative clinicopathological study of large cell neuroendocrine carcinoma and small cell lung carcinoma

Large cell neuroendocrine carcinoma (LCNEC) and small cell lung carcinoma (SCLC) are high-grade neuroendocrine carcinomas. In order to clarify the similarities and differences between these cancers, 22 cases each of LCNEC and SCLC were collected and a comparative pathological study was carried out. First, their clinicopathological characteristics were confirmed, which were very similar to those previously reported. The 5 year survival rate of LCNEC and SCLC patients was 38.3% and 29.7%, respectively. The morphological characteristics of LCNEC and SCLC were then reviewed with regard to the morphology previously used to differentiate these cancers. As a result, many morphological indicators, such as tumor cell size, nuclear/cytoplasmic ratio, nuclear molding, rosette formation, prominent nucleoli and karyolysis were confirmed to be significant indicators for distinguishing LCNEC from SCLC. On comparative immunohistochemistry, LCNEC had significantly high staining scores for the expression of keratin 7 and 18, E- and P-cadherins, β-catenin, villin 1, retinoblastoma protein (pRB), c-met and α-enolase. These results might reflect the differentiation or deviation of LCNEC toward an epithelial nature irrespective of neuroendocrine tumor lineage. In conclusion, the present comparative study of LCNEC and SCLC defined the similarities and differences between these cancers, and showed the biologically and clinicopathologically overlapping spectrum of the tumor lineage.     

Cytokeratin expression profiling is useful for distinguishing between primary squamous cell carcinoma of the lung and pulmonary metastases from tongue cancer

It can be difficult to distinguish between primary and metastatic squamous cell carcinoma (SCC) in the lung. Surgical specimens were obtained from two groups of patients, 26 lung SCC patients without histories of any other cancer (the definite primary group) and 17 patients who had undergone surgical removal of SCC emerging in the lung after surgery for tongue SCC (the unknown group). From the former, 26 primary lung SCC were obtained. From the latter, 17 lung tumors and 15 primary tumors of the tongue were obtained. Eleven of the 17 lung tumors from the unknown group were metastatic lung SCC. All specimens were immunostained with cytokeratin (CK)5/6, CK7, CAM5.2, CK19 and p63 antibodies. The frequency of CAM5.2 and CK19 expression was significantly higher in the lung SCC of the definite primary group (21 of 26, 81% and 20 of 26, 78%, respectively) than in the metastatic lung SCC (1 of 11, 9% (P < 0.001) and 2 of 11, 18% (P= 0.003), respectively) or primary SCC of the tongue (5 of 15, 33% (P= 0.002) and 2 of 15, 13% (P < 0.001), respectively). CAM5.2 and CK19 are useful for distinguishing between primary SCC of the lung and metastases from tongue cancer.     

Immunohistochemical differential diagnosis between large cell neuroendocrine carcinoma and small cell carcinoma by tissue microarray analysis with a large antibody panel

To elucidate additional phenotypic differences between large cell neuroendocrine carcinoma (LCNEC) and small cell lung carcinoma (SCLC), we performed tissue microarray (TMA) analysis of surgically resected LCNEC and SCLC specimens. Immunostaining with 48 antibodies was scored based on staining intensity and the percentage of cells that stained positively. Four proteins were identified as significantly expressed in LCNEC as compared with SCLC: cytokeratin (CK)7, 113 vs 49 (P < .0301); CK18, 171 vs 60 (P < .0008); E-cadherin, 77 vs 9 (P < .0073); and beta-catenin, 191 vs 120 (P < .0286). Immunostaining of cross-sections containing LCNEC and SCLC components revealed significant expression of CK7, CK18 and beta-catenin in the LCNEC component compared with the SCLC component in 2 of 3 cases. Our results indicate that significant expression of CK7, CK18, E-cadherin, and beta-catenin is more characteristic of LCNEC than of SCLC, and these findings provide further support that these tumor types are separate entities morphologically and immunophenotypically, if not biologically.     

Squamous cell carcinomas. An immunohistochemical study of cytokeratins and involucrin in primary and metastatic tumours

The expression of cytokeratins (CK) 1, 4, 5/6, 8, 13, 18, 19 and 20 and involucrin in 42 cases of squamous cell carcinomas from various locations was examined. The tumours expressed CK5/6 in 55%, CK8 in 76%, CK13 in 43% and CK19 in 95% of cases. The CK5/6-positive primary tumours were from uterine cervix, head and neck, lung, skin, oesophagus is and urinary bladder, and the CK13-positive primary tumours were from uterine cervix, lung and vulva. Metastatic squamous cell carcinomas from head and neck more frequently expressed CK5/6 and 13, 7/7 (100%) and 6/7 (86%) compared with 3/5 (60%) and 0/5 (0%) in the primary squamous cell carcinomas. Few cases were CK1, CK4 and CK18 immunoreactive, CK20 immunoreactivity was not observed. Involucrin was expressed in 71% of tumours, and most of the involucrin-positive cells were located at the central parts of tumour cell clusters except for one case in which the peripheral cells around tumour cell clusters were positive. Thus, expression of the so-called simple epithelial markers CK8 and CK19 occurs in the majority of squamous cell carcinomas. The absence of CK20 immunoreactivity may be helpful in differential diagnosis.     

Small cell carcinoma of the lung and large cell neuroendocrine carcinoma interobserver variability

den Bakker M A, Willemsen S, Grünberg K, Noorduijn L A, van Oosterhout M F M, van Suylen R J, Timens W, Vrugt B, Wiersma‐van Tilburg A & Thunnissen F B J M
(2010) Histopathology 56, 356–363 Small cell carcinoma of the lung and large cell neuroendocrine carcinoma interobserver variability Aims: To test the hypothesis that the published morphological criteria permit reliable segregation of small cell carcinoma of the lung (SCLC) and large cell neuroendocrine carcinoma (LCNEC) cases by determining the interobserver variation. Methods and results: One hundred and seventy cases of SCLC, LCNEC and cases diagnosed as neuroendocrine lung carcinoma before LCNEC had been established as a diagnostic category were retrieved from the archives of the assessor’s institutes. A representative haematoxylin and eosin section from each case was selected for review. Batches of cases were circulated among nine pathologists with a special interest in pulmonary pathology. Participants were asked to classify the cases histologically according to the 2004 World Health Organization (WHO) criteria. The diagnoses were collected and κ values calculated. Unanimity of diagnosis was achieved for only 20 cases; a majority diagnosis was reached for 115 cases. In 35 cases no consensus diagnosis could be reached. There was striking variability amongst assessors in diagnosing SCLC and LCNEC. The overall level of agreement for all cases included in this study was fair (κ = 0.40). Conclusions: Using non‐preselected cases, the morphological WHO criteria for diagnosing SCLC and LCNEC leave room for subjective pathological interpretation, which results in imprecise categorization of SCLC and LCNEC cases.     

Expression of intermediate filament proteins in subtypes of renal cell carcinomas and in renal oncocytomas. Distinction of two classes of renal cell tumors

We examined the expression of the diverse cytokeratin (CK) polypeptides as well as vimentin in human renal cell carcinomas of various subtypes and in renal oncocytomas by applying both two-dimensional gel electrophoresis and immunocytochemistry by using polypeptide-specific monoclonal antibodies. The tumors were classified according to the guidelines of the World Health Organization, with some modifications based primarily on recently proposed cytomorphological criteria. All clear cell carcinomas (G I, G II; N = 20) co-expressed CKs nos. 8 and 18, and vimentin, with CK no. 19 being present in 13 of the 20 cases and exhibiting a heterogeneous distribution. Dedifferentiated carcinomas (G III; N = 8) also co-expressed CKs nos. 8 and 18 as well as vimentin, but in addition, exhibited CK no. 19 and, in many cases, CK no. 7; in 1 case, only vimentin was expressed. Both eosinophilic-granular (N = 3) and basophilic (small cell cuboidal; N = 6) carcinomas contained CKs nos. 8 and 18, and the co-expression of vimentin was a consistent feature of these tumors; CK no. 19 was found in all of these cases, while CK no. 7 was present in the majority. In chromophobe cell carcinomas (N = 8), in contrast to all of the other carcinoma types, no vimentin was detected in the tumor cells, with only CKs nos. 8, 18, and to a variable extent 7, being present. Similarly, oncocytomas (N = 8) lacked vimentin and exhibited only CKs nos. 8 and 18. Conspicuous scattered CK no. 19-positive cells were found in these two last tumor types. No CK polypeptides other than simple-epithelium-type CKs (nos. 7, 8, 18, and 19) were detected in any of the tumors studied. These results indicate that, in renal cell tumors, the expression of intermediate-filament proteins is strikingly correlated with the specific morphologic appearance. While the co-expression of CKs nos. 8 and 18 and vimentin was a surprisingly consistent feature of the most common subtypes of renal cell carcinomas, CK no. 19 exhibited remarkable heterogeneity of expression both within individual tumors and between different tumors, the expression patterns of this CK being correlated to the tumor subtypes. The consistent absence of vimentin in chromophobe cell carcinomas and oncocytomas makes it possible to define these as a separate class of renal cell tumors. This finding supports the view that chromophobe cell carcinomas represent a distinct tumor entity and points to their close phenotypic relationship to benign oncocytomas as well as to normal renal tubules.     

The many faces of acinic cell carcinomas of the salivary glands: a study of 40 cases relating histological and immunohistological subtypes to clinical parameters and prognosis

Schwarz S, Zenk J, Müller M, Ettl T, Wünsch P H, Hartmann A & Agaimy A
(2012) Histopathology  61, 395–408 The many faces of acinic cell carcinomas of the salivary glands: a study of 40 cases relating histological and immunohistological subtypes to clinical parameters and prognosis Aims: To study the morphological heterogeneity of acinic cell carcinoma (ACC) in correlation with clinicopathological parameters. Methods and results: Forty well‐characterized ACCs were classified as solid (n = 20), microcystic (n = 15), papillary‐cystic (n = 4) or follicular (n = 1), based on the dominant architectural growth pattern. Fourteen tumours exhibited eosinophilic/clear cell morphology and 18 tumours were rich in zymogen granules (so‐called blue dot tumours). High‐grade morphology occurred in five tumours. Based on cytokeratin (CK) 7 staining and in analogy to CK7 expression in normal salivary gland epithelia, three distinct histogenetic subtypes were recognized: acinar (CK7‐negative; n = 13), ductular (diffuse CK7‐positive; n = 11) and mixed ductulo‐acinar (10–66% CK7‐positive cells; n = 16). Most papillary‐cystic tumours displayed ductular differentiation (P = 0.015), whereas blue dot tumours never did (P < 0.001). Analysis of relapse‐free survival (RFS) revealed that Stage I tumours had the best prognosis without any relapse in 18 years follow‐up (P = 0.06). High‐grade tumours were associated with shorter RFS (P = 0.028). Concerning the histogenetic types, monophasic (pure acinar or ductular) tumours were associated with a significantly better RFS than mixed ductulo‐acinar tumours (P = 0.008). Conclusion: The results underscore the great histological diversity of ACC, and the value of histogenetic subtyping as an additional prognostic factor regarding RFS.     

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.     

Prognostic role of insulin‐like growth factor receptor‐1 expression in small cell lung cancer

Chang MH, Lee J, Han J, Park YH, Ahn JS, Park K, Ahn M‐J. Prognostic role of insulin‐like growth factor receptor‐1 expression in small cell lung cancer. APMIS 2009; 117: 861–9. Insulin‐like growth factor receptor‐1 (IGFR‐1) is a cellular membrane receptor which is overexpressed in many tumors and seems to play a critical role in anti‐apoptosis. The insulin‐like growth factor binding protein‐3 (IGFBP‐3) is known as a growth suppressor in multiple signaling pathways. The aim of this study was to determine IGFR‐1 and IGFBP‐3 expression in small‐cell lung cancer (SCLC) and analyze the prognostic value in patients with SCLC. We analyzed IGFR‐1 and IGFBP‐3 expression in 194 SCLC tissues by immunohistochemical staining. Correlative analyses between IGFR‐1 and IGFBP‐3 expression in SCLC and clinicopathologic factors were performed. A total of 117 patients had extensive disease (ED) (60.3%) and 77 had limited disease (39.7%). With the median follow‐up duration of 49.5 months (24–82 months), the median progression‐free survival (PFS) and overall survival (OS) were 7.2 months [95% confidence interval (CI): 6.4–8.0 months] and 14.4 months (95% CI: 12.7–16 months), respectively. IGFR‐1 expression was observed in 154 of the 190 tumor tissues, whereas there was no IGFBP‐3 expression. Multivariate analysis showed that stage (p < 0.001), response rate (p < 0.001), and lactate dehydrogenase (LDH) levels (p < 0.001) were the independent prognostic factors for PFS, and age (p = 0.014), LDH level (p < 0.001), and stage (p < 0.001) for OS. The IGFR‐1 positivity was not associated with PFS or OS in the entire cohort. Subgroup analysis revealed that OS was significantly longer in patients with IGFR‐1‐positive tissue than IGFR‐1‐negative tissue in SCLC‐ED (p = 0.034). These results suggest that IGFR‐1 expression may be useful as a prognostic marker in patients with SCLC‐ED.     

CD117 expression in operable oesophageal squamous cell carcinomas predicts worse clinical outcome

Aims

To investigate the aberrant expression of CD117 in oesophageal squamous cell carcinoma (SCC) and its prognostic significance.

Methods and results

Immunohistochemical staining for CD117 was performed on tissue microarray and routine tissue sections from 157 oesophageal SCC patients and 10 normal oesophageal epithelia adjacent to tumour. The positive rate of CD117 expression was 29.9% in oesophageal SCC tissues, whereas no CD117 expression was detected in the 10 normal oesophageal epithelia. CD117 expression was significantly associated with T stage (P < 0.001), distant metastasis (P = 0.015), lymph node metastasis (P = 0.019), and clinical stage (P = 0.021). Progression‐free survival in the patients with CD117‐positive tumours was shorter than that in the patients with CD117‐negative tumours (P = 0.010). In univariate analyses, CD117 expression was the most significant factor for overall survival of oesophageal SCC patients (P < 0.001), followed by lymph node metastasis (P = 0.001), T stage (P = 0.002), clinical stage (P = 0.006), distant metastasis (P = 0.020), and histological grade (P = 0.027). Multivariate analyses verified that CD117 expression was an independent prognostic marker for oesophageal SCC patients (P = 0.002). In addition, CD117 expression predicted poorer survival in patients without distant metastases.

Conclusions

CD117 expression in operable oesophageal SCC may be a valuable prognostic marker, and detection of its expression in clinical samples may be useful in defining a subclass of oesophageal SCCs with extremely poor clinical outcome, which may require a specially targeted treatment modality.     

Increased expression of REV7 in small cell lung carcinomas and its association with tumor cell survival and proliferation

REV7 is involved in multiple biological processes including DNA damage tolerance, cell cycle regulation and gene expression, and is an accessory subunit of the mutation-prone DNA polymerase ζ. It has been reported that REV7 expression is associated with poor prognosis in several human cancers. The aim of this study is to investigate the significance of REV7 in lung carcinogenesis. Immunohistochemical analyses of surgically resected lung cancer specimens revealed that REV7 shows an increased expression in small cell lung carcinomas (SCLCs) when compared with other histological types of lung carcinoma. Association between REV7 expression levels and clinicopathological factors was investigated using SCLC cases with or without surgical resection. Our analyses revealed that high REV7 expression significantly correlated with tumor cell proliferation, assessed by Ki-67 labeling indices, and was negatively associated with distant metastasis and extensive-stage disease. No significant association was detected between REV7 expression and other factors, including prognosis or response to chemoradiotherapy in SCLC. Increase in REV7 expression in SCLC was confirmed using SCLC cell lines. In addition, siRNA-mediated depletion of REV7 activated the apoptotic pathway and suppressed cell growth in SCLC cells. These results suggest that REV7 plays an important role in tumor cell survival and proliferation in SCLC.     

The genetic landscape of endometrial clear cell carcinomas

Clear cell carcinoma of the endometrium is a rare type of endometrial cancer that is generally associated with an aggressive clinical behaviour. Here, we sought to define the repertoire of somatic genetic alterations in endometrial clear cell carcinomas (ECCs), and whether ECCs could be classified into the molecular subtypes described for endometrial endometrioid and serous carcinomas. We performed a rigorous histopathological review, immunohistochemical analysis and massively parallel sequencing targeting 300 cancer‐related genes of 32 pure ECCs. Eleven (34%), seven (22%) and six (19%) ECCs showed abnormal expression patterns for p53, ARID1A, and at least one DNA mismatch repair (MMR) protein, respectively. Targeted sequencing data were obtained from 30 of the 32 ECCs included in this study, and these revealed that two ECCs (7%) were ultramutated and harboured mutations affecting the exonuclease domain of POLE. In POLE wild‐type ECCs, TP53 (46%), PIK3CA (36%), PPP2R1A (36%), FBXW7 (25%), ARID1A (21%), PIK3R1 (18%) and SPOP (18%) were the genes most commonly affected by mutations; 18% and 11% harboured CCNE1 and ERBB2 amplifications, respectively, and 11% showed DAXX homozygous deletions. ECCs less frequently harboured mutations affecting CTNNB1 and PTEN but more frequently harboured PPP2R1A and TP53 mutations than non‐POLE endometrioid carcinomas from The Cancer Genome Atlas (TCGA). Compared to endometrial serous carcinomas (TCGA), ECCs less frequently harboured TP53 mutations. When a surrogate model for the molecular‐based TCGA classification was used, all molecular subtypes previously identified in endometrial endometrioid and serous carcinomas were present in the ECCs studied, including POLE, MMR‐deficient, copy‐number high (serous‐like)/p53 abnormal, and copy‐number low (endometrioid)/p53 wild‐type, which were significantly associated with disease‐free survival in univariate analysis. These findings demonstrate that ECCs constitute a histologically and genetically heterogeneous group of tumours with varying outcomes. Furthermore, our data suggest that the classification of ECCs as being generally ‘high‐grade’ or ‘type II’ tumours may not be warranted. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.     

Cytokeratin expression in non-neoplastic oesophageal epithelium and squamous cell carcinoma of the oesophagus

The expression of cytokeratins (CK) 19, 8, 18, 13, 10 and 7 was examined in 35 cases of squamous cell carcinomas of the oesophagus (10 well-differentiated, 13 moderately-differentiated, and 12 poorly-differentiated) and the adjacent mucosa by means of a panel of monoclonal antibodies on frozen sections. The study was undertaken to assess the pattern of expression of these keratins in oesophageal tumours and its relation to the degree of differentiation. The normal oesophageal epithelia expressed CK19 in 86%, CK18 in 17% and CK13 in 14% of cases. CK8, CK10 and CK7 immunoreactivity was not observed. The tumours expressed CK19 in 86%, CK8 in 46%, CK18 in 97%, CK13 in 83%, CK10 in 34% and CK7 in 29% of cases. Thus, the so-called simple epithelial markers CK18 and CK19 occurred in the majority of oesophageal squamous cell carcinomas. CK13 (the so-called non-keratinizing squamous epithelial marker) was only infrequently demonstrated in the non-neoplastic oesophageal mucosa, and its expression was more frequent in carcinomas. CK10 was not demonstrated in non-neoplastic mucosa, but was mostly associated with well-differentiated carcinomas. We therefore conclude that the pattern of expression of cytokeratins in oesophageal carcinomas is different from that in normal oesophageal epithelia and varies with differentiation.     

Relation between hyaluronan synthesis and cell morphology in ovarian clear cell carcinomas

Ovarian clear cell carcinomas often show a spherule‐like mucoid stroma. In ascitic fluid, they form spheroids with a hollow acellular space. In spite of the absence of stromal cells, both the mucoid stroma and hollow spheroids contain abundant extracellular matrix, and one of the major components is hyaluronan. It has been suggested that tumor‐derived hyaluronan plays a significant role in the formation of these structures. To clarify this, a hyaluronan inhibition assay was performed on HAC‐2, a clear cell carcinoma cell line, in vitro. When hyaluronan synthesis was inhibited by 4‐methylumbelliferone, HAC‐2 failed to show the spherule‐like accumulation of hyaluronan or hollow spheroids. Inhibition of hyaluronan synthesis was associated with the reduction of cell growth. Analysis of 28 archival ascites cytology specimens showed that clear cell carcinomas expressed hyaluronan more frequently than serous carcinomas (11 of 14 vs 3 of 14, respectively, P < 0.05). All of these facts indicate that tumor‐derived hyaluronan is essential for the formation of the mucoid stroma or hollow spheroids, and that hyaluronan is also involved in the regulation of cell growth in ovarian clear cell carcinomas. The inhibition of hyaluronan synthesis could be a potential adjunctive therapy for refractory clear cell carcinomas outside the ovary.     

p63, CK7, PAX8 and INI-1: an optimal immunohistochemical panel to distinguish poorly differentiated urothelial cell carcinoma from high-grade tumours of the renal collecting system

Carvalho J C, Thomas D G, McHugh J B, Shah R B & Kunju L P
(2012) Histopathology  60, 597–608
p63, CK7, PAX8 and INI‐1: an optimal immunohistochemical panel to distinguish poorly differentiated urothelial cell carcinoma from high‐grade tumours of the renal collecting system Aims: High‐grade, poorly differentiated, infiltrative carcinomas involving the renal sinus region often pose challenging differential diagnostic considerations, specifically differentiation of urothelial carcinoma (UC) from renal cell carcinoma (RCC) subtypes. Accurate classification, especially the distinction of UC from RCC, is critical, as therapeutic approaches differ. Methods and results: Cluster analysis was performed on immunohistochemical data from 18 invasive UCs, six CDCs, two RMCs, 18 type 2 papillary renal cell carcinomas (PRCCs) and 20 high‐grade clear cell renal cell carcinomas (CRCCs) using a broad panel of traditional and novel immunohistochemical markers. The initial analysis with all antibodies segregates almost all the RCCs (45 of 46, 98%) from all the UCs based on the lack of expression of p63 in all (100%) RCCs, along with predominant strong expression of paired box gene 8 (PAX8) and vimentin, predominant lack of expression of high molecular weight cytokeratin (HMCK) and CK7 and variable expression of RCC, CD10, CA1X and PAX2. All the UCs cluster together with strong, diffuse reactivity for p63, predominant reactivity for CK7 and high molecular weight kininogen (HMWK), and absent to minimal staining with PAX8, RCC antigen, PAX2, alpha‐methylacyl‐CoA racemase (AMACR), carbonic anhydrase IX (CAIX) and vimentin. After removing antibodies with significant overlap and/or minimal impact, a second analysis with a limited panel including p63, CK7, vimentin, integrase interactor 1 (INI‐1) and PAX8 was performed. Again, the majority of UCs cluster into one group and p63 positivity separates all UCs from RCCs. Conclusions: Lack of INI‐1 expression, noted exclusively in RMCs, segregates RMCs into a separate cluster. PAX8 is rarely positive (17%) in UC, is commonly expressed in CDC, RMC, PRCC and CRCC and is superior to PAX2.     

Expression of vascular endothelial growth factor in renal cell carcinomas

Vascular endothelial growth factor (VEGF) is an angiogenic factor that may be involved in tumor growth and metastasis. Only a few data concerning the role of VEGF in renal cell carcinomas (RCCs) are available, and no studies have yet evaluated its prognostic value. The aim of the present study was to assess VEGF expression in a large series of renal tumors with a long follow-up, correlated with the usual histoprognostic factors and survival. VEGF immunostaining was performed on formalin-fixed, paraffin-embedded archival tissue from 74 renal carcinomas (62 conventional renal cell and 12 papillary carcinomas). Positivity of immunostaining was semi-quantitatively scored by two pathologists. Angiogenesis was evaluated by immunostaining with anti-CD34 antibodies on serial sections. Cytoplasmic VEGF expression was detected in tumor cells in 35% (26/74) of RCCs, including 18 out of the 62 (29%) conventional RCCs and 8 out of the 12 (67%) papillary carcinomas (P=0.02). In the group of conventional RCCs, VEGF expression was positively correlated with both nuclear grade (P=0.05) and size of the tumor (P=0.05). Furthermore, a significant correlation was observed between VEGF expression and microvascular count (P=0.04). Finally, cumulative survival rate was significantly lower in the group of patients with conventional RCCs expressing VEGF (log rank test, P=0.01). In the Cox model, VEGF expression was a significant independent predictor of outcome, as well as stage and nuclear grade. This study suggests that VEGF is involved in angiogenesis in conventional RCCs and appears to be a potential prognostic factor in these tumors. Received: 9 July 1999 / Accepted: 18 October 1999     

Non-small cell lung carcinomas with a minor sarcomatoid component and pleomorphic carcinomas are associated with high expression of programmed death ligand 1

Pleomorphic carcinomas are known to be highly programmed death ligand 1 (PD-L1) positive non-small cell lung cancer (NSCLC) types. However, the level of PD-L1 expression in lung carcinomas with a minor sarcomatoid component, comprising less than 10 % of the tumor mass, has not been determined yet. We hypothesized that NSCLC with a minor sarcomatoid component is more closely related to pleomorphic carcinomas in terms of PD-L1 expression than to NSCLC types without sarcomatoid features. The surgical resections from 690 lung carcinoma patients were retrospectively analyzed for the presence of PD-L1 by means of immunohistochemistry using the 22C3 PharmDx assay. The tumor proportion score system was applied to quantify the level of PD-L1 expression. Membranous staining present in ≥ 1 % of tumor cells was chosen as the cut-off to define a positive result for PD-L1 expression. Tumors were allocated into one of four subgroups: “adenocarcinoma”, “squamous cell carcinoma”, “pleomorphic carcinoma”, or “NSCLC with a minor sarcomatoid component”. PD-L1 expression in pleomorphic carcinomas (26/32, 81.3 %) and in the subgroup of NSCLC with a minor sarcomatoid component (35/46, 76.1 %) was identified in a comparable proportion of cases. Pleomorphic carcinomas were significantly more often PD-L1 positive than adenocarcinomas (p < 0.001) or squamous cell carcinomas (p = 0.0015). Accordingly, the proportion of PD-L1 expressing NSCLC with a minor sarcomatoid component was significantly higher than that of the adenocarcinoma (p < 0.001) or squamous cell carcinoma (p = 0.002) subgroup. In summary, we identified a presumable new subgroup of highly PD-L1 positive neoplasms within the NSCLC spectrum that is related to pleomorphic carcinomas in terms of PD-L1 expression. Further investigation regarding genetic relation and mechanism of PD-L1 expression in these two NSCLC categories is recommended.     

High-grade neuroendocrine carcinomas of the lung express K homology domain containing protein overexpressed in cancer but carcinoid tumors do not

K homology domain containing protein overexpressed in cancer (KOC) is a member of the insulin-like growth factor (IGF) messenger RNA-binding protein family and is expressed during embryogenesis and in certain malignancies. KOC, known as L523S and IGF messenger RNA-binding protein 3, was shown to be frequently expressed in high-grade neuroendocrine carcinomas of the lung in our immunohistochemical studies using a monoclonal antibody against human KOC. Specifically, all 10 small cell lung carcinomas (SCLCs) exhibited strong cytoplasmic staining, 9 with diffuse positivity and 1 with focal positivity. Among 14 large cell neuroendocrine carcinomas (LCNECs), 9 exhibited strong and diffuse cytoplasmic staining, and 5 cases showed focal immunoreactivity. In contrast, no KOC was detected in 21 typical and atypical carcinoids, except for one atypical carcinoid with oncocytic cells showing weak cytoplasmic staining. Although SCLCs exhibited a strong and diffuse staining pattern more frequently (90%) than LCNECs (64%), the difference did not reach statistical significance (P = .3408). Interestingly, our immunohistochemical studies demonstrated that IGF-II, reportedly regulated by KOC, was comparably expressed in SCLC, LCNEC, and typical and atypical carcinoids, irrespective of KOC expression status of the tumors. These results support the formulation that KOC may play an important role in the regulation of biologic behavior of high-grade neuroendocrine carcinomas. In addition, detection of KOC expression may be diagnostically useful in distinguishing high-grade neuroendocrine carcinomas from carcinoid tumors. Our findings of equivalent IGF-II expression in KOC-positive SCLC and LCNEC and KOC-negative carcinoid tumors suggest different regulatory mechanisms involved in the control of IGF-II expression in these tumors.