No abstract

Introduction: DNA mismatch repair (MMR) deficiency is associated with increased risk of developing several types of cancer and is the most common cause of hereditary endometrial cancer. Identification of the microsatellite instability (MSI) phenotype in endometrial carcinoma is important given that such tumors are frequent. Objective: The objective of this study was to assess the utility of immunohistochemistry (IHC), a simple and fast technique, in detecting MSI status in endometrial carcinoma and evaluate the correlation between the MSI phenotype and the various anatomo-clinical parameters. Methods: IHC expression of 4 markers (MLH1, MSH2, PMS2, and MSH6) was studied. For all IHC markers, a combined score based on the intensity of nuclear labeling and the percentage of labeled cells was defined to establish a score. Correlation between MSI phenotype and different clinicopathologic parameters was evaluated using statistical analysis (software STATA and the Fisher exact test). Results: The mean age of the patients was 58.6 years. Positive staining was highly extended (score 3) with 79% to 100% of marked cells. Less than 10% of positive tumor cells were seen in 3% of cases for MSH6 and PMS2. Abnormal MMR IHC was detected in 10 cases (22.22%). Seven tumors showed loss of MLH1/PMS2. The loss of MSH2/MSH6 was observed in 1 case. The loss of MLH1 or PMS2 was seen only in 2 cases. The number of MSI positive status was 10 cases (22.7%). Correlation between clinicopathologic parameters showed MMR deficiency was significantly associated with low-grade tumor and localized stage. There was no positive correlation between age, histologic subtype, or myometrium invasion. Conclusions: In summary, detection of DNA MMR deficiencies by IHC can effectively diagnose the MSI phenotype in endometrial carcinoma. Correlation between clinicopathologic parameters showed MMR deficiency was significantly associated with low-grade tumor and localized stage.

Adamantinoma is a rare tumour of long bones, representing less than 1% of them. Adamantinoma commonly occurs in the tibia. It is locally aggressive and recurrences are uncommon after resection. Metastases have been reported in less than 10% of cases. The most common radiographic appearance is multiple sharply demarcated radiolucent lesions surrounded by areas of dense sclerotic bone. The authors report a patient who developed pulmonary metastasis 1 year after complete resection of primary neoplasm.

No abstract

Retinoblastoma, an embryonic neoplasm of retinal origin, is the most common primary intraocular malignancy in children. Somatic inactivation of both alleles of the RB1 tumor suppressor gene in a retinal progenitor cell through diverse mechanisms including genetic and epigenetic modifications, is the crucial event in initiation of tumorigenesis in most cases of isolated unilateral retinoblastoma. We analyzed DNA from tumor tissue and from peripheral blood to determine the RB1 mutation status and seek correlations with clinical features of 37 unrelated cases of Tunisian origin with sporadic retinoblastoma. All cases were unilateral except one who presented with bilateral disease, in whom no germline coding sequence alteration was identified. A multi-step mutation scanning protocol identified bi-allelic inactivation of RB1 gene in 30 (81%) of the samples tested. A total of 7 novel mutations were identified. There were three tumors without any detectable mutation while a subset contained multiple mutations in RB1 gene. The latter group included tumors collected after treatment with chemotherapy. There were seven individuals with germline mutations and all presented with advanced stage of tumor. There was no difference in age of onset of RB based on the germline mutation status. Thus 20% of the individuals with sporadic unilateral RB in this series carried germline mutations and indicate the importance of genetic testing all children with sporadic retinoblastoma. These findings help to characterize the spectrum of mutations present in the Tunisian population and can improve genetic diagnosis of retinoblastoma.