Summary DNA methyltransferase 1, 3a, and 3b affect DNA methylation, and it is thought that they play an important role in the malignant transformation of various cancers. The current study was designed to analyze DNA methyltransferase expression by immunohistochemistry in a series of 94 Tunisian sporadic breast carcinomas. Results were correlated to clinicopathologic parameters and promoter methylation status of 8 tumor suppressor genes (BRCA1, BRCA2, RASSFA1, TIMP3, CDH1, P16, RARβ2, and DAPK). Overexpression of DNA methyltransferase 1, 3a, and 3b was detected in 46.8%, 32%, and 44.7% of cases, respectively. A significant correlation was found between DNA methyltransferase 1 overexpression and Scarff-Bloom-Richardson histologic grade III (P = .01). DNA methyltransferase 3a overexpression was significantly associated with menopausal status (P = .01), Scarff-Bloom-Richardson histologic grade III (P = .0001), estrogen (P = .04) and progesterone (P = .007) receptor negativity, and HER2 overexpression (P = .004). However, DNA methyltransferase 3a overexpression was found less frequently in the luminal A intrinsic breast cancer subtype (9.7%) than in luminal B (53%), HER2 (41%), and triple-negative (50%) subtypes (P = .001). DNA methyltransferase 3b overexpression shows significant correlation with promoter hypermethylation of BRCA1 (P = .03) and RASSFA1 (P = .04) and with the hypermethylator phenotype (more than 4 methylated genes, P = .01). These data suggest that overexpression of various DNA methyltransferases might represent a critical event responsible for the epigenetic inactivation of multiple tumor suppressor genes, leading to the development of aggressive forms of sporadic breast cancer.

The occurrence of primary sex cord-stromal tumors at extraovarian sites is exceedingly rare. We report a new case of Sertoli-Leydig cell tumor in the mesentery of a 78-year-old woman who presented with occlusive syndrome and reviewed the previously reported cases of extraovarian sex cord-stromal tumors in the English literature.

Background: Ovarian mucinous carcinoma has a poor prognosis in advanced stages and a poor response to conventional chemotherapy. An efficient treatment is not yet available. We heere investigated HER2 expression and the potential for trastuzumab therapy in ovarian mucinous tumors. Materials and Methods: Immunohistochemistry was performed in formalin-fixed, paraffin-embedded tissue from 27 ovarian mucinous tumors including 14 carcinomas and 13 borderline tumors diagnosed in the Pathology Department, Farhet Hached Hospital, Sousse, between 1993 and 2013. The HercepTest (DAKO) was used for immunohistochemistry. Results: HER2 expression was observed in only one borderline tumor (7.7%) and in 14.3% of mucinous carcinomas of the ovary. Conclusions: Our results suggest that trastuzumab therapy would be an option for patients with mucinous carcinoma when the tumor has HER2 overexpression.

Background: The role of p16 INK4A expression in uterine cervix cancer is well established. In the remaining female lower genital tract cancers, the importance of p16 INK4A up-regulation is less clear. In our study, we analyzed the role of p16 INK4A expression and HPV infection in carcinomas of the vulva and the vagina in Tunisian women. Materials and Methods: We conducted a retrospective study of 30 carcinomas including 15 vulvar squamous cell carcinomas (SCCs) and 15 vaginal SCCs. Immunohistochemistry was used to determine p16 INK4A expression. HPV detection and typing was by in situ hybridization. Results: p16 INK4A expression was detected in 86.7% of vaginal SCCs with a strong and diffuse immunostaining in 60% of cases, and also in 73.3% of vulvar SCCs with focal immunoreactivity in 53.3% The association between p16 INK4A expression and HPV infection was significant in vaginal SCCs (p=0.001) but not vulvar SCCs (p>0.05). Conclusions: p16 INK4A expression could be used as a useful marker for HPV positivity in vaginal SCCs similar to that described in uterine cervix cancers. However, our data support the presence of 2 different mechanisms for p16 INK4A expression in HPV-related and HPV-unrelated vulvar carcinomas.

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