Ovarian small cell carcinoma of hypercalcemic type - evidence of germline origin and SMARCA4 gene inactivation. a pilot study.

Ovarian tumors from two patients, compatible by histological and immunohistochemical criteria with small cell carcinoma of hypercalcemic type (SCCHT) (WT1+, EMA dispersed+, synaptophysin+ or dispersed+), were extensively sampled in order to find clues to their histogenesis. Subsequently, small foci of immature teratoma were found in both of them (in 1/122 and in 3/80 tumor sections). In one case, microfoci of yolk sac tumor were also present within the teratoma area as well as in the background of the small cell tumor population - in the primary tumor and in omental metastasis. We found a resemblance of the microscopic patterns of SCCHT and atypical teratoid/rhabdoid tumor (AT/RT) of the central nervous system, and this prompted us to evaluate INI-1 and SMARCA4 immunohistochemical expression, because their alternative loss is regarded as a molecular hallmark of AT/RT. INI-1 expression was retained, while that of SMARCA4 was lost. We therefore analyzed tumor DNA by PCR amplification and sequencing for mutations in the SMARCA4 gene (NG_011556.1), which were identified in both tumors (c.2184_2206del; nonsense c.3277C>T - both in one tumor; nonsense c.3760G>T in another tumor). These data suggest that SCCHT is most likely an embryonal tumor originating from immature teratoma and related to malignant rhabdoid tumor. Further analyses are necessary to determine whether the tumors diagnosed as SCCHT constitute a homogeneous group or represent more than one entity.

TP53 status determines clinical significance of ERBB2 expression in ovarian cancer.

ERBB2 expression has been found in 19 to 44% of ovarian carcinomas; however, its predictive value has not been demonstrated, and trastuzumab has not found clinical application in ovarian cancer patients. We evaluated clinical significance of ERBB2 expression in relation to TP53 accumulation in ovarian carcinoma patients treated with platinum-based regimens. Immunohistochemical analysis with CB11 and a novel NCL-CBE356 antibody (against the internal and external domains of ERBB2, respectively) was performed on 233 tumours (FIGO stage IIB-IV); the US Food and Drug Administration-approved grading system with 0 to 3+ scale was used for evaluation, and the results were analysed by the Cox and logistic regression models. In all, 42% of the tumours expressed (category 1+, 2+ or 3+) either CB11 or CBE356 or both (CB11/CBE356 parameter). Associations between ERBB2 expression and clinical factors were observed only if tumours with staining category 1+ were grouped together with tumours showing staining categories 2+ and 3+. CB11/CBE356 parameter had a better predictive value than CB11 alone. CB11/CBE356 expression was negatively associated with platinum sensitivity (PS) in the TP53(-) group (P=0.022) and with disease-free survival (DFS) in the TP53(+) group (P=0.009). Our results may suggest that trastuzumab should be given postoperatively to patients with TP53(-)/ERBB2(+) ovarian carcinomas to enhance PS, and after completion of chemotherapy to patients with complete remission and TP53(+)/ERBB2(+) carcinomas to extend DFS time (in total to 30.4% of all patients analysed). Thus, novel criteria for ovarian cancer patient inclusion for clinical trials with trastuzumab should be considered and tested.

P21WAF1, P27KIP1, TP53 and C-MYC analysis in 204 ovarian carcinomas treated with platinum-based regimens.

BACKGROUND: The prognostic and predictive value of cell cycle regulatory proteins in ovarian cancer has not been established. We evaluated the clinical and biological significance of P21(WAF1), P27(KIP1), C-MYC, TP53 and Ki67 expressions in ovarian cancer patients. MATERIALS AND METHODS: Immunohistochemical analysis was performed on 204 ovarian carcinomas of International Federation of Gynecology and Obstetrics (FIGO) stage IIB to IV treated with platinum-based chemotherapy. Multivariate analysis with Cox and logistic regression models was performed in the whole group, and in the TP53-negative and TP53-positive subgroups. RESULTS: High P21(WAF1) labeling index (LI) was an independent positive predictor of platinum-sensitive response (P = 0.02). Overall survival was positively influenced by P21(WAF1) LI (P = 0.02) or by P21(WAF1) plus P27(KIP1) LI (P = 0.004) in the TP53-negative group only. Ki67 LI showed borderline association with disease-free survival (P = 0.05). Growth fraction was negatively associated with P21(WAF1) and P27(KIP1) indices in the TP53-negative group (P = 0.023 and 0.008, respectively), and these associations were borderline or lost in the TP53-positive group. Endometrioid and clear cell carcinomas differed from other carcinomas by having a low incidence of TP53 accumulation, a high incidence of C-MYC overexpression (70%) and a low median Ki67 LI (all with P <0.001). CONCLUSIONS: We have shown an independent predictive value of P21(WAF1) LI in ovarian carcinoma patients. The prognostic value of P21(WAF1) and P21(WAF1) plus P27(KIP1) LI was determined by TP53 status. A high frequency of C-MYC overexpression in endometrioid and clear cell carcinomas may suggest its role in the development of these tumor types.

Nijmegen breakage syndrome gene (NBS1) alterations and its protein (nibrin) expression in human ovarian tumours.

We looked for NBS1 gene (602667) alterations and changes in nibrin expression in 162 human gynaecological tumours, mostly ovarian. Exons 6-8 and 10 of the NBS1 gene were evaluated by the SSCP and direct sequencing method. Nibrin expression was detected immunohistochemically with the use of the p95NBS1 (Ab-1) antibody. The 657del5 mutation (Slavic mutation) was found in two of 117 carcinomas studied (1.7%) - in both cases it was present in the germline; one of these tumours showed loss of heterozygosity (LOH) for the 657del5 mutation and loss of nibrin expression. We have found three types of novel germline intron variants: (1) two concomitant transitions (G to A) at bases 14009 and 14256; (2) C to T transition at base 13998; (3) G to C transversion at base 20035. Among the carcinomas studied, the intron variants were associated with a clear cell histological type (p = 0.004). Our results may suggest that NBS1 gene alterations contribute to the development of rare ovarian carcinomas. LOH for 657del5 in tumour tissue may support the hypothesis that the NBS1 gene functions as a tumour suppressor.