Relationship between promoter methylation & tissue expression of MGMT gene in ovarian cancer.

Background & objectives: Epigenetic alterations, in addition to multiple gene abnormalities, are involved in the genesis and progression of human cancers. Aberrant methylation of CpG islands within promoter regions is associated with transcriptional inactivation of various tumour suppressor genes. O6-methyguanine-DNA methyltransferase (MGMT) is a DNA repair gene that removes mutagenic and cytotoxic adducts from the O6-position of guanine induced by alkylating agents. MGMT promoter hypermethylation and reduced expression has been found in some primary human carcinomas. We studied DNA methylation of CpG islands of the MGMT gene and its relation with MGMT protein expression in human epithelial ovarian carcinoma. Methods: A total of 88 epithelial ovarian cancer (EOC) tissue samples, 14 low malignant potential (LMP) tumours and 20 benign ovarian tissue samples were analysed for MGMT promoter methylation by nested methylation-specific polymerase chain reaction (MSP) after bisulphite modification of DNA. A subset of 64 EOC samples, 10 LMP and benign tumours and five normal ovarian tissue samples were analysed for protein expression by immunohistochemistry. Results: The methylation frequencies of the MGMT gene promoter were found to be 29.5, 28.6 and 20 per cent for EOC samples, LMP tumours and benign cases, respectively. Positive protein expression was observed in 93.8 per cent of EOC and 100 per cent in LMP, benign tumours and normal ovarian tissue samples. Promoter hypermethylation with loss of protein expression was seen only in one case of EOC. Interpretation & conclusions: Our results suggest that MGMT promoter hypermethylation does not always reflect gene expression.

Bone marrow involvement at presentation in pediatric non-haematological small round cell tumours.

Pediatric small round cell tumors (SRCT) are a group of neoplasms occurring in children, which have in common a cytomorphology of groups of small round cells with scanty cytoplasm. The common SRCT encountered are neuroblastoma, retinoblastoma, Ewing's sarcoma/peripheral neuroectodermal tumor (PNET), rhabdomyosarcoma and lymphoma which show varying degrees of bone marrow involvement and bone marrow evaluation forms a part of the initial staging procedure. This study was undertaken to evaluate marrow involvement at presentation in pediatric non hematological SRCT. 7833 bone marrow aspirates done over a period of three years in different malignancies were analysed and of these 180 aspirates were performed in patients of pediatric non hematological SRCT at presentation. These cases were evaluated in detail for incidence of marrow involvement. Thirty two (17.7%) cases showed marrow involvement and these cases have been analysed with respect to the primary tumor. The SRCT showing involvement of bone marrow included neuroblastoma (48.8%), retinoblastoma (11.1%), Ewing's sarcoma/PNET (8.6%) and rhabdomyosarcoma (3.2%).These findings are discussed in the light of available world literature.

Childhood hepatic angiosarcoma--a case report.

Hepatic angiosarcoma (HAS) is an extremely rare liver tumor in children. We report a case of childhood HAS in a six year old girl who presented with acute abdominal pain and fever with a mass in epigastrium. Left hepatic lobectomy was performed with a clinical diagnosis of hepatoblastoma. Histopathological examination revealed features typical of hepatic angiosarcoma. The case is presented for its rarity and to discuss the interrelation between infantile hemangioendothelioma (IHE) and HAS.