Photoreceptor cell differentiation in retinoblastoma demonstrated by a new immunohistochemical marker mucin-like glycoprotein associated with photoreceptor cells (MLGAPC)

AIMS: For further understanding of specific differentiation in retinoblastoma, we studied the expression of newly detected mucin-like glycoprotein associated with photoreceptor cells (MLGAPC), which is specific for photoreceptor cells of retina and analogous to interphotoreceptor matrix proteoglycan-1 (IMPG1). METHODS AND RESULTS: Surgically enucleated retinoblastomas (n=21; undifferentiated type, n=15, differentiated type, n=6) were immunohistochemically studied with a polyclonal antibody against MLGAPC, and 17/21 cases (81%) showed positive staining of tumour cells. We classified various staining patterns and structures into four groups: type 1 showing a granular intracellular scattered staining pattern with round small cells; type 2 showing a reticular staining pattern between spindle-shaped tumour cells; type 3 showing radiating staining from the centre of Homer-Wright rosettes; type 4 showing ring-shaped, radiating and granular staining associated with Flexner-Wintersteiner rosettes. Eleven of 15 undifferentiated retinoblastomas (73%) showed type 1 or 2, and all the six differentiated cases showed type 3 or 4. Image analysis of immunostaining revealed an increase in MLGAPC-positive area from 0.48% in undifferentiated cases to 1.60% in differentiated cases, and a negative correlation was shown between mitotic frequency and MLGAPC-positive area. CONCLUSIONS: This study proved MLGAPC as a valuable marker of retinoblastoma, and that photoreceptor differentiation takes place even in 'undifferentiated' retinoblastoma.     

Neuron-associated class III beta-tubulin isotype, microtubule-associated protein 2, and synaptophysin in human retinoblastomas in situ. Further immunohistochemical observations on the Flexner-Wintersteiner rosettes.

We studied by immunohistochemistry 26 retinoblastomas in situ using monoclonal antibodies specific for the neuron-associated class III beta-tubulin isotype (h beta 4), microtubule-associated protein 2 (MAP2), and synaptophysin. Anti-h beta 4 and anti-MAP2 immunostaining was consistently obtained in the Flexner-Wintersteiner rosettes, in fleurettes, in Homer Wright (neuroblastic) rosettes, and also variably among poorly differentiated tumor cells. A similar pattern of antisynaptophysin immunopositivity was seen, but was especially pronounced in the adluminal borders of cells forming the Flexner-Wintersteiner rosettes. The demonstration of h beta 4, MAP2, and synaptophysin epitopes in poorly differentiated and maturing neoplastic phenotypes in retinoblastomas attests to the neuronal character of this embryonal tumor. Immunoreactivity toward h beta 4 and MAP2 epitopes by poorly differentiated neoplastic cells may indicate early neuronal commitment in retinoblastoma. The consistent immunostaining of Flexner-Wintersteiner rosettes with monoclonal antibodies to h beta 4 and MAP2 is in keeping with the previous ultrastructural documentation of microtubules with a neuronal-like spatial organization present in the cells of these structures.     

Photoreceptor differentiation of retinoblastoma: An electron microscopic study of 29 retinoblastomas

Retinoblastomas exhibit a unique form of differentiation to produce cell elements similar to those seen in a photoreceptor cell. An ultrastructural study was performed on 29 cases of retinoblastoma to further clarify the cytologic characteristics of the tumor cells. The age of the retinoblastomas averaged 17.1 months and the tumor cells showing photo-receptor differentiation were demonstrated in 10 cases (35%). The findings were especially notable in retinoblastomas with Flexner-Wintersteiner rosette formation (seven cases, 28%). Similar photoreceptor differentiation was also evident in solid cell clusters without rosette formation (four cases, 14%). The presence of photoreceptor elements was assumed to be significantly frequent both in Flexner-Wintersteiner rosettes and in the solid cell clusters. The cell cytoplasm also showed proliferation of long mitochondria and microtubules, reflecting photoreceptor differentiation. The hereditary-type retinoblastoma showed more advanced cell differentiation than the non-hereditary type. Photoreceptor differentiated retinoblastoma showed rather indolent growth compared with the undifferentiated type, and the former can expect a curative treatment by operation. These observations provide additional findings of the biological nature of retinoblastomas.     

Overexpression of DNA methyltransferases 1, 3a, and 3b significantly correlates with retinoblastoma tumorigenesis

DNA methyltransferases (DNMTs) 1, 3a, and 3b affect DNA promoter methylation; studies have suggested that they have important roles in the development of cancers. In this study, we analyzed the expression of DNMTs 1, 3a, and 3b; the MIB-1 labeling index; and their clinical significance in 6 normal retinas and 62 retinoblastomas using immunohistochemical analysis. We found that DNMT proteins were not expressed in normal retinas, whereas they were frequently expressed in retinoblastomas (DNMT1, 100%; DNMT3a, 98%; and DNMT3b, 92%). Compared with well-differentiated retinoblastomas, the expression of DNMTs 1 and 3a significantly increased in poorly differentiated retinoblastomas (P = .002 and P = .003, respectively); in addition, the frequency of their increased expression was high. DNMT1 expression was significantly higher in invasive retinoblastoma. Furthermore, the expression of DNMTs was positively correlated with the MIB-1 labeling index in retinoblastoma. Our findings suggest that the overexpression of DNMTs 1, 3a, and 3b may be related to retinoblastoma tumorigenesis and progression and may represent a novel approach for retinoblastoma therapy.     

Phosphorylation of p27(KIP1) in the developing retina and retinoblastoma

Cellular distribution of the p27(KIP1) protein and its phosphorylation on threonine (T) 187 in mouse retinas from three stages of development, and retinoblastoma were examined. Retinas in C57Bl6 mice at embryonic day (E) 14, postnatal day (P) 1 and P11 were analyzed using immunohistochemistry with anti-p27(KIP1), threonine-187-phosphorylated p27(KIP1) (T187-phospho-p27), bromodeoxyuridine (BrdU), proliferating cell nuclear antigen (PCNA) antibodies, and phosphorylated histon H3 (pHiston H3), which is a marker for cells in M phase. p27(KIP1) knockout (-/-) mice and human retinoblastoma were also analyzed. T187-phospho-p27 was detected in the outermost layer of the retina, whereas several neuroblastic cells expressed p27(KIP1) at E14. Many neuroblastic cells expressed BrdU in the middle layer. At P1, p27(KIP1) was detected in the ganglion cell layer and neuroblastic layer. T187-phospho-p27 was detected in the outermost layer, and that was localized in mitotic cells that also showed pHiston H3-positive. At P11, p27(KIP1) was detected in the inner nuclear layer, whereas T187-phospho-p27-positive or mitotic cells were not. BrdU positive nuclei were not detected in wild-type but were noted in the inner nuclear layer and the outer nuclear layer of the p27(KIP1) -/- mice retina at P11. In retinoblastoma, tumor cells formed numerous rosettes with Flexner-Wintersteiner rosettes. Several pHiston H3 -positive nuclei were noted in the tumor cells forming Flexner-Wintersteiner rosettes. Several T187-phospho-p27-positive nuclei were also detected in the mitotic cells forming Flexner-Wintersteiner rosettes. PCNA was expressed in rosette-forming cells. In conclusion, T187-phospho-p27(KIP1) was correlated with M phase of the cell cycle in the developing retina and retinoblastoma.     

Higher vessel densities in retinoblastoma with local invasive growth and metastasis

In this study, the importance of angiogenesis (the growth of new blood vessels from existing ones) for the growth of retinoblastoma was investigated by a retrospective immunohistochemical analysis. An individual vessel index for each tumor was determined using the endothelial-specific antibody CD 31 for vessel staining. The obtained data were correlated with clinical features, pathohistological characteristics, and the presence of metastasis. In 107 retinoblastomas collected between 1980 and 1990, we found no difference in the vessel densities between uni- and bilateral retinoblastomas (P = 0.41). However, tumors that had invaded the chorioid and/or the optic nerve statistically showed higher vessel densities than tumors without local invasive growth (P = 0.05 and P = 0.024). A tendency of higher vessel densities in retinoblastomas presenting with metastasis at the time of diagnosis was observed (P = 0.11). Based on this observation, we proceeded to examine all retinoblastomas presenting with metastasis at the time of diagnosis. These included patients that were treated between 1968 and 1993. The 18 investigated retinoblastomas had significantly higher vessel densities than all other retinoblastomas presenting without metastasis (P = 0.025). Our data indicate that in retinoblastoma, blood vessels are essential for local and systemic invasive growth. Therefore, an anti-angiogenic therapy could be considered in the multimodal therapy concept for retinoblastomas with invasive growth, both locally and systemically.     

Correlation of p53 and MIB-1 expression with both the systemic recurrence and survival in cases of phyllodes tumors of the breast

Phyllodes tumors are rare primary tumors of the breast. The study aimed at evaluating the immunohistochemical features of phyllodes tumors of the breast that may be useful for predicting the clinical outcome. We examined the immunohistochemical expression of the epidermal growth factor receptor (EGFR), HER2/neu, CD117/c-kit, p53, and MIB-1, and analyzed correlations between the immunohistochemical findings and the clinical outcome. The study included 41 patients with phyllodes tumor (20 benign, 5 borderline, and 16 malignant). Systemic recurrence occurred in 9 patients. The 2-year survival rate was 84%, and the 2-year recurrence-free survival rate was 77%. Six patients developed systemic recurrence within the first year after surgery. None of the phyllodes tumors was positive for HER2/neu or CD117/c-kit. Positive staining for p53 was seen in 10 phyllodes tumors (24%), and the median MIB-1 index was 10%. Both p53 expression and the MIB-1 index, but not the expression status of EGFR, were significantly correlated with the recurrence-free and overall survival. p53 expression status and MIB-1 index may be significant prognostic factors in patients with phyllodes tumors, and careful postoperative follow-up may be important in those cases showing positive expression of p53 and/or MIB-1 index.     

Immunohistochemical expression of CD117 and vascular endothelial growth factor in retinoblastoma: possible targets of new therapies

CD117 (C-kit) is thought to play an important role in tumourigenesis. There are limited data in the literature concerning C-kit expression in retinoblastoma. To date, no immunohistochemical studies have been performed to assess the possible association of C-kit with vascular endothelial growth factor (VEGF) in retinoblastoma. This study was designed to investigate C-kit and VEGF immunoexpression in retinoblastoma, their relationship with prognostic parameters as well as the correlation between them. A prospective immunohistochemical study was conducted on 56 retinoblastoma cases. Patients who had received preoperative chemotherapy were excluded. Positive C-kit and VEGF immunoreactivity was observed in 48.2% and 76.8% of retinoblastoma cases respectively. No C-kit immunostaining was seen in the adjacent uninvolved retina. However, VEGF expression was detected within its vasculature. Retinoblastomas with combined pattern of tumour growth revealed a highly significant positive C-kit expression (P = 0.002) compared to cases with endophytic or exophytic growths. Also, positive C-kit expression was statistically higher in cases with optic nerve invasion (P = 0.001) and choroidal invasion (P ≤ 0.01) compared to negative cases. A highly significant positive VEGF expression was detected in cases with optic nerve invasion (P = 0.013) compared to negative cases. Moreover, a highly significant positive correlation was detected between C-kit and VEGF expression (P = 0.006). C-kit is a feature of more aggressive retinoblastomas, with increased expression in tumours spreading beyond the retina. Moreover, VEGF is vastly expressed in retinoblastoma and is associated with optic nerve invasion. Both C-kit and VEGF may represent potential therapeutic targets for retinoblastomas.     

Correlation between histological grade, MIB-1, p53, and recurrence in 69 completely resected primary intracranial meningiomas with a 6 year mean follow-up

Sixty-nine intracranial, totally excised meningiomas were immunostained for MIB-1 and p53 protein expression. According to the 1993 WHO criteria, revised by Perry et al., the 69 meningiomas were classified into: grade I = 54 benign meningiomas, grade II = 10 atypical meningiomas, grade III = 5 malignant meningiomas. The patients were followed until death or for an average of 6.7 years. The 69 meningiomas were divided into two groups, according to the absence (n = 42) or presence (n = 27) of recurrences. In the last group we included 3 patients who died of meningioma recurrence. According to the percentage of MIB-1 positively stained cells, meningiomas were divided into three groups: <1% (n = 36), 1-10% (n = 28), >10% (n = 5). We found the MIB-1 labeling index (LI) <1% in 33 grade I (61%) and in 3 grade II (30%) meningiomas. On the other hand, 7 grade II (70%) and all grade III (100%) meningiomas presented a MIB-1 LI >1%. Correlation between histological grade and MIB-1 LI was statistically significant (p = 0.0006). The correlation between MIB-1 LI and follow-up was also highly significant (p < 0.001): the majority of meningiomas which did not recur (32/42 equal to 76%) were characterized by a low (<1%) MIB-1 LI. In the recurrence group MIB-1 LI was significantly higher than in the disease-free patients' group. Moreover, MIB-1 appeared to be a prognostic parameter not strongly related to the histological grade. In fact, it was significantly higher in recurrent histologically benign meningiomas, as compared with benign meningiomas without recurrence (p = 0.0006). Positive p53 protein expression (>1%) was shown in 26/45 meningiomas (57%), with an LI of 1-10% in 18 (40%) and an LI of >10% in 8 (17%) meningiomas. Although the p53 LI tended to be higher in atypical and malignant meningiomas, no significant correlation was found between the p53 expression and the recurrence (p = 0.05). The authors conclude that quantitative MIB-1 labeling is a useful technique in the routine diagnostic assessment of meningiomas, and helpful in obtaining more information about prognosis and thereby in planning the most suitable treatment.     

p53, cellular proliferation, and apoptosis-related factors in thymic neuroendocrine tumors.

Thymic neuroendocrine tumors are biologically aggressive neoplasms with extensive local invasion and high mortality. Although various markers of cellular proliferation and apoptosis have correlated with degrees of tumor differentiation in pulmonary neuroendocrine neoplasms, they have not been systematically studied in thymic neuroendocrine tumors. We immunostained 21 cases of thymic neuroendocrine tumors for p53, MIB-1, and the apoptosis-related markers Bcl-2, Bcl-x, and Bax. By histological classification the cases were low-grade (nine cases), intermediate-grade (eight cases), and high-grade (four cases) thymic neuroendocrine tumors. p53 was expressed in five cases: 1/9 low grade, 3/8 intermediate grade, and 2/4 high grade. The mean cellular proliferation (MIB-1) was 7.1% (range 2-12%) in low-grade thymic neuroendocrine tumors, 6.1% (range 2-15%) in intermediate-grade thymic neuroendocrine tumors, and 34.2% (range 2-80%) in high-grade thymic neuroendocrine tumors. Bcl-2 was expressed in 16 cases: 7/9 low grade, 5/8 intermediate grade, and 4/4 high grade. Bcl-x was expressed in 16 cases: 7/9 low grade, 6/8 intermediate grade, and 3/4 high grade. Bax was expressed in 13 cases: 5/9 low grade, 4/8 intermediate grade, and 4/4 high grade. The presence of mutant p53 in the tumor was associated with a statistically significant decreased mean survival (P<0.05). In contrast, either by positive or negative staining or by the score technique (staining intensity x percentage of cells staining), the presence of Bcl-x was associated with an increased mean survival (P<0.05). Finally, a Bcl-x : Bax ratio >or=1 was also associated with an increased mean survival, as compared to a Bcl-x : Bax ratio >or=1 (P<0.05). Our study shows that p53 expression and certain apoptosis markers correlate with survival. The expression of these markers may account for differences in biological behavior.     

Esophageal small cell carcinomas: clinicopathologic parameters, p53 overexpression, proliferation marker, and their impact on pathogenesis

OBJECTIVE: To evaluate the clinicopathologic features and the roles of p53 and MIB-1 in esophageal small cell carcinoma. METHOD: Twenty patients (14 men and 6 women) with esophageal small cell carcinoma treated in our hospital from 1982 through 1996 were studied. The clinicopathologic features, treatment received, and survival data of these patients were documented. Representative tissue was collected from each tumor, and immunohistochemical preparations for p53 protein and MIB-1 were made. RESULTS: Small cell carcinoma accounted for 1.3% of all esophageal malignant tumors. The median age of patients at presentation was 60 years. On gross examination, the tumors were large ulcerative lesions (median length, 7.5 cm). In 17 patients in whom p53 immunohistochemical study was performed, p53 protein was detected in 65% (9 of 17). All stage IV tumors were negative for p53 expression. The median tumor cell MIB-1 score was high at 855 (range, 810-964) positive cells per 1000. Overall median survival was 3.4 months. In patients who underwent chemotherapy, there was significant response. CONCLUSIONS: Esophageal small cell carcinoma is an aggressive tumor. Overexpression of p53 is associated with early stages of carcinogenesis. The high proliferative index, as defined by the MIB-1 immunohistochemical method, may be related to aggressive behavior and high sensitivity to chemotherapy and radiotherapy.     

MIB-1 (Ki-67), p53, estrogen receptor, and progesterone receptor expression in uterine smooth muscle tumors

The diagnosis of benign, uncertain malignant potential, and malignant uterine smooth muscle tumors depends on mitotic counts, nuclear atypia, and other morphologic features. This study was undertaken to evaluate the utility of selected immunohistochemical markers in differentiating these tumors. Fifteen cases of cellular leiomyoma, 7 cases of smooth muscle tumor of uncertain malignant potential (STUMP), and 12 cases of leiomyosarcoma were immunostained for MIB-1 (Ki-67), p53, estrogen receptor and progesterone receptor (PR) using monoclonal antibodies and the avidin-biotin-peroxidase method. The percentage of cells stained was subjectively assessed to the nearest 5%. One percent was used for rare positive cells. MIB-1 expression of > or =15% was seen in 11 and expression of p53 in > or =15% cells was present in 5 of 12 leiomyosarcomas. MIB-1 and/or p53 expression of >15% was seen in all 12 leiomyosarcomas but in none of the 7 STUMP or 15 cellular leiomyomas. PR was absent in 10 of 12 leiomyosarcomas but present in 7 of 7 STUMP and 14 of 15 cellular leiomyomas. MIB-1 of 5% to 10% was seen in 6 of 7 STUMP but in only 1 of 15 cellular leiomyomas. MIB-1, p53, and PR are useful in differentiating leiomyosarcoma from STUMP and cellular leiomyoma. MIB-1 is useful in distinguishing STUMP from cellular leiomyomas.     

A study of 39 retinoblastomas with particular reference to morphology, cellular differentiation and tumour origin

A series of 39 retinoblastomas was studied using light microscopy and immunohistochemistry for localization of neurone-specific enolase and glial fibrillary acidic protein. Thirty-eight retinoblastomas (97.4%) occurred in children less than 6 years of age: one was in a 61-year-old man (2.6%); the mean age, excluding the 61-year-old, was 32.1 months. Unilateral tumours were found in 74.4% of patients and bilateral tumours in 25.6%; bilateral lesions occurred in a younger age group, mean age of 21.7 vs 35.9 months. The male to female ratio was 1.4:1. Morphologically, arrangement of tumour cells into trabeculae was noted in 69.2% of retinoblastomas and glomerulus-like structures in 43.6%. These two patterns of cellular arrangement were encountered where the choroid and sclera were invaded by neoplastic cells. Homer Wright rosettes were observed in all tumours. Flexner-Winstersteiner rosettes in 33.3% and fleurettes in 2.6%. Differentiation into neoplastic neurones as well as in the form of Flexner-Winstersteiner rosettes and fleurettes was noted in 46.1%, neoplastic ependymal cells in 100.0%, astrocytes in 58.9%, oligodendrocytes in 23.1%, and glioblastomas in 2.6%. These data suggest that retinoblastoma is a primitive stem cell neuroectodermal tumour with the capacity for differentiation in both neuronal and neuroglial directions.     

Subependymomas: clinicopathologic study of 14 tumors, including comparative MIB-1 immunohistochemical analysis with other ependymal neoplasms.

BACKGROUND: Subependymomas are uncommonly encountered ependymal tumors, which are important to distinguish from ordinary ependymomas because of their generally better prognosis. OBJECTIVE: To review the clinicopathologic features and MIB-1 labeling indices (marker of cell proliferation) of 14 subependymomas. DESIGN: Retrospective review of 14 subependymomas encountered in a tertiary care setting. RESULTS: Fourteen ependymomas presenting in 8 men and 6 women between the ages of 18 and 78 years (mean, 53.6 years) comprise the study group. The most common clinical presentations included ataxia (n = 4), dizziness/vertigo (n = 3), nausea/vomiting (n = 3), headaches (n = 3), and incidental finding at autopsy (n = 2). Tumor locations included fourth ventricle (n = 7), lateral ventricle (n = 4), third ventricle (n = 2), and thoracic spinal cord (n = 1). Eight patients underwent gross total resection, and 4 had subtotal resection. Tumors were characterized by clustering of cell nuclei arranged against a fibrillary background. Focal cystic degeneration was seen in 10 tumors, hemosiderin deposition in 8 tumors, sclerotic vessels in 8 tumors, calcifications in 5 tumors, and focal nuclear pleomorphism in 2 tumors. Mitotic figures, vascular endothelial proliferation, and necrosis were not seen in any of these tumors. Cell proliferation marker MIB-1 labeling indices (percentage of positive staining tumor cells) ranged from 0 to 1.4 (mean, 0.3). In comparison, 13 myxopapillary ependymomas had labeling indices ranging from 0 to 5.5 (mean, 1.1). Thirty-nine low-grade ependymomas had MIB-1 labeling indices of 0.1 to 5.4 (mean, 1.1). Fourteen anaplastic/malignant ependymomas had MIB-1 labeling indices ranging from 0.4 to 34.0 (mean, 12.8). One subependymoma was treated with radiation therapy. Six patients were alive with no evidence of tumor at a mean follow-up of 94.4 months. Two patients were alive with residual tumor (follow-up of 4 and 53 months). Two patients died with tumor at 0.67 and 43.4 months. One patient was lost to follow-up, 1 is a recent case, and 2 were incidental findings at autopsy. None of the patients developed tumor recurrence. CONCLUSIONS: Subependymomas are generally low-grade lesions, as evidenced by their benign clinical course and low MIB-1 labeling indices. Compared with other ependymal tumors, subependymomas have the lowest rate of cell proliferation as evidenced by MIB-1 immunostaining.     

Markers of proliferative activity are predictors of patient outcome for low-grade endometrioid adenocarcinoma but not papillary serous carcinoma of endometrium.

On the basis of pathogenesis, two types of endometrial cancer can be recognized. Type 1 endometrial carcinomas are relatively indolent tumors that develop after prolonged estrogen stimulation, on a background of endometrial hyperplasia. Type 2 endometrial carcinomas are aggressive tumors that are not associated with hyperplasia or estrogen excess. The aim of this study is to evaluate the prognostic significance of tumor proliferative activity in early-stage endometrial cancer by using mitotic index and immunostaining, comparing Type 1 (endometrioid) and Type 2 (papillary serous carcinoma) tumors. The mitotic index, MIB-1, and p53 immunostaining in 39 tumors from patients with low-grade Stage Ia or Ib endometrioid adenocarcinoma; as well as 23 tumors from patients with Stage I papillary serous carcinoma. In low-grade endometrioid adenocarcinoma, mitotic and MIB-1 indices were statistically significant independent prognostic indicators (P =.004 and P =.018, respectively), and both were strongly correlated with p53 expression (P =.01 and P =.006, respectively). The mean mitotic index was 5 mitoses/10 high-power fields, and mean MIB-1 index was 27.5%. There was no significant correlation between mitotic or MIB-1 indices and patient outcome or p53 expression in papillary serous carcinoma. The mean mitotic index was 31 mitoses/10 high-power fields, and mean MIB-1 index was 30.5% in these tumors. p53 expression and proliferative indices are strongly correlated in low-grade endometrioid adenocarcinoma. MIB-1 and mitotic indices are independent prognostic indicators in these tumors. Papillary serous carcinoma of endometrium is rapidly proliferative in tumors even at an early stage, and quantification of proliferative activity in these tumors does not allow prediction of patient outcome.     

Aspiration cytology of retinoblastoma: light and electron microscopic correlations

A series of 16 cases of retinoblastoma diagnosed by fine-needle aspiration biopsy (FNAB) and confirmed by histologic examination is reviewed, and the salient cytomorphologic features are described. Two types of cells were encountered in the aspiration smears; type I cells were undifferentiated while type II cells showed more differentiation and frequently revealed cytoplasmic processes that are probably indicative of early photoreceptor differentiation. Flexner-Wintersteiner rosettes characteristic of retinoblastoma were found in 10 of 16 cases. These findings were further correlated with ultrastructural examination of the tumors in nine cases. It is concluded that the presence of rosettes and type II cells with cytoplasmic processes are the two features that are most helpful in the FNAB diagnosis of retinoblastoma.     

Correlation of Ki-67 and p53 with the new World Health Organization/International Society of Urological Pathology Classification System for Urothelial Neoplasia

OBJECTIVE: The present study examines p53 and Ki-67 staining patterns of the diagnostic entities included within the new World Health Organization/International Society of Urological Pathology (WHO/ISUP) classification of urothelial neoplasms. DESIGN: We retrospectively studied 151 bladder biopsies from 81 patients with the following neoplasms: normal urothelium (n = 34 biopsies); low-grade intraurothelial neoplasia (LGIUN; n = 19); high-grade intraurothelial neoplasia (HGIUN; n = 20); papillary hyperplasia (n = 4); papilloma (n = 3); papillary neoplasm of low malignant potential (LMP; n = 12); low-grade papillary carcinoma (n = 28); and high-grade papillary carcinoma (n = 31). Sections were labeled immunohistochemically with antibodies to p53 and Ki-67 (MIB-1). Two hundred cells from each lesion were visually counted, and the percentage of positive cells was tabulated without knowledge of the WHO/ISUP diagnosis. RESULTS: In flat lesions, p53 positivity was of limited diagnostic utility; the marker was present in 6 of 34 benign biopsies, 6 of 19 LGIUNs, and 10 of 20 HGIUNs. In one case in which HGIUN was present elsewhere in the bladder, 29% of the benign urothelial cells were p53 positive. In papillary lesions, p53 positivity was not seen in 4 of 4 cases of papillary hyperplasia, 3 of 3 papillomas, and 8 of 12 LMP tumors. In contrast, p53 was detected in 18 of 28 low-grade and 26 of 31 high-grade papillary urothelial carcinomas. A p53 labeling index (LI) greater than 30% was only seen in HGIUNs and high-grade papillary carcinomas. In flat lesions, an increased Ki-67 LI separated out benign urothelium (mean LI, 0.62%) from dysplasia (mean LI, 3.3%) and HGIUN (mean LI, 11.6%). In papillary lesions, Ki-67 positivity was as follows: papillary hyperplasia (mean LI, 1.1%); papilloma (mean LI, 4.3%); LMP tumors (mean LI, 2.5%), low-grade papillary carcinoma (mean LI, 7.3%); and high-grade carcinoma (mean LI, 15.7%). A Ki-67 LI greater than 10% was seen only in low- and high-grade papillary carcinomas, HGIUN, and single cases of LGIUN and papillary neoplasm of LMP. CONCLUSIONS: An increased proliferative index as demonstrated by immunohistochemical staining for Ki-67 (MIB-1) is most often seen in papillary carcinoma and HGIUN. Marked p53 positivity is also characteristic of carcinoma but may be seen in benign-appearing urothelium, suggesting a "field effect" with occult molecular aberration.     

Apoptotic and proliferative markers in chordomas: a study of 26 tumors

Few studies have examined the role of cell proliferation and apoptotic markers in chordomas. This study retrospectively reviews the clinicopathologic features of 26 chordomas and examines MIB-1, p53, bcl-2, and cyclin D1 immunoreactivity in these neoplasms. Patients ranged in age from 34 to 78 years (mean, 60.7 years) and included 14 females. The most common presentations included lower back pain (N = 15) and headaches (N = 10). Sixteen tumors arose in the lumbosacral region and 10 in the clivus. Initial surgery included biopsy (N = 17), subtotal resection (N = 4), and gross total resection (N = 5). The single highest mitosis count per 10 high power fields ranged from 0 to 6 (mean, 1). Marked nuclear pleomorphism was identified in seven tumors. Marked hypercellularity was seen in two tumors. Focal necrosis was identified in seven tumors. MIB-1 labeling indices (LI) in 22 tumors ranged from 0 to 3.8 (mean, 0.5). Cyclin D1 LI ranged from 0 to 82.4 (mean, 35.6). Seven tumors had positive p53 immunostaining and three demonstrated focal positive staining with bcl-2 antibody. Five tumors locally recurred; two patients developed metastatic disease. Thirteen patients received adjuvant chemotherapy and/or radiation therapy. At last known follow-up, seven patients died with tumor (12 to 132 months follow-up). Five additional patients died, two without tumor at 36 and 72 months follow-up and three patients in whom the tumor status at death was not known. Seven patients were alive with evidence of tumor (1 to 120 months) and five patients were alive without evidence of tumor (12 to 84 months). Clinical follow-up was not available in one patient. In conclusion, the low MIB-1 LIs and the lack of p53 and bcl-2 staining is in keeping with the low-grade nature of most chordomas. High cyclin D1 LIs may be reflective of a tendency to accumulate cyclin D1 protein; however, there appears to be a block in the effect of cyclin D1 on cell proliferation in these tumors. Cyclin D1, MIB-1, p53, and bcl-2 immunostaining does not appear to improve one's ability to predict behavior versus routine light microscopy.     

Proliferative Activity in Pancreatic Endocrine Tumors: Association with Function,Metastases, and Survival

Endocrine tumors of the pancreas are slow-growing lesions, yet one-third to one-half will metastasize. It is generally accepted that histopathologic features do not reliably predict metastatic potential or outcome. We investigated whether proliferative activity, as determined by MIB-1 labeling, correlated with tumor type, metastasis, or patient survival. Formalin-fixed sections of pancreatic endocrine tumors were immunohistochemically stained for the MIB-1 antibody against Ki-67 using the avidin-biotin complex technique. Labeling index (LI) was determined by counting 1000 consecutive tumor cells in an area of greatest staining intensity at ×400 and expressed as a percentage. The study group included 37 patients, including 10 gastrinomas, 9 insulinomas, 4 glucagonomas, 2 VIPomas, and 12 nonfunctioning tumors. Twenty-one patients had metastases, primarily to regional lymph nodes and the liver. Five patients had MEN I. MIB-1 LI was significantly greater in the nonfunctioning tumors (mean 20.9%) than in the functioning tumors (mean 5.1%) (p = 0.01). LI for functional tumors (insulinomas 6.4%, glucagonoma 4.4%, gastrinomas 3.2%, VIPomas 3.2%) were similar to each other. MIB-1 was significantly higher in those tumors that metastasized (mean 15.6%) compared to those that did not (mean 3.1%), (p = 0.04). All tumors with MIB-1 LI≥10% developed metastases. Logistic regression showed that MIB-1 was a significant predictor of metastases (p = 0.003) after adjusting for functional status. MIB-1 LI also correlated with outcome in that those patients with MIB-1 LI ≥10% had a mean survival of 19 mo compared to 72 mo for those with levels <10% (p = 0.0001). Results of the proportional hazards model showed that MIB-1 remained a significant (p = 0.03) and independent predictor of survival times after adjustment for tumor size and functional status. Higher MIB-1 LI values, were significantly associated with shorter survival times. In conclusion, MIB-1 LI appears to be a useful indicator of metastatic potential and is predictive of outcome in PET.     

Muscle invasive schistosomal squamous cell carcinoma of the urinary bladder: frequency and prognostic significance of p53, BCL-2, HER2/neu, and proliferation (MIB-1)

Muscle invasion is the usual presentation of schistosomal squamous cell carcinoma of the urinary bladder. It is unclear whether this invasive behavior is secondary to the aggressive nature of the disease or to delay in diagnosis. Fixed paraffin-embedded hematoxylin and eosin-stained sections of 15 cystectomy specimens from 15 patients (14 males, 1 female) (age range, 40 to 67 years), histologically confirmed as schistosomal squamous cell carcinoma, were assessed for grade (G1, n = 3; G2, n = 7; G3, n = 5) and pathological stage (PT category: PT2, n = 4; PT3a, n = 9; PT3b, n = 2). Immunostaining was performed for mutant p53, bcl-2, HER2/neu, and MIB-1 (proliferation), using steam antigen retrieval and an avidin-biotin complex method. Frequency of strong immunoreactivity was high for mutant p53 (73%) and MIB-1 (87% intermediate or high) but low for bcl-2 (20%) and HER2/neu (27%). There was no significant correlation of any of the four markers with either grade or stage. Hence, schistosomal bladder squamous cell carcinoma is felt to be an aggressive carcinoma de novo. The high frequency of mutant p53 expression (73%) and an intermediate to high proliferation index (87%) suggests this. The lack of correlation between histological grade and all four markers studied suggests that grading is not of prognostic value.