Cell cycle regulators cyclin D1 and cyclin E2 function in G1/S transition by activating downstream cyclin-dependent kinases. Deregulated expression of these cyclins has been reported in various cancers. However, little is known about their clinical significance in gastric carcinoma. We aimed to explore that whether there is differential expression of these cyclins in clinically distinct gastric cancer patients. In this study we recruited a total of 92 subjects including 20 controls and 72 cases of histopathologically proven gastric carcinoma. Expression profiling at transcript level was done by semiquantitative RT-PCR and of protein by immunohistochemistry. Receiver operator characteristics analysis was done for determining diagnostic utility of cyclin D1 and cyclin E2. We demonstrate that cyclins D1 and E2 are frequently overexpressed in early stages of gastric carcinoma. Interestingly, expression of cyclins D1 and E2 significantly correlates with different clinical parameters such as gender, histological type (intestinal and diffuse), tumor location (proximal, middle, and distal), tumor differentiation (differentiated and undifferentiated), tumor invasion (serosal, lymphatic, and venous) and tumor metastasis (lymph node, peritoneal, ascites, and liver). Cyclin D1 has significantly higher sensitivity and specificity as diagnostic biomarker than cyclin E2. Our results suggest that overexpression of cyclin D1 and cyclin E2 is an early event in gastric carcinogenesis. The differential expression of these cyclins may be useful as diagnostic biomarkers for early detection of gastric carcinoma.

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Gastric cancer remains highly prevalent and accounts for a notable proportion of global cancer mortality and this is associated with poor survival rates. Understanding the molecular genetic changes of gastric carcinoma may offer an insight into its pathogenesis helps in identifying new biomarkers, aid prognostication, and novel treatment targets. Over a past few decades, advances in technology and high throughput analysis have improved understanding of the molecular genetic aspects of gastric cancer. In this article, hierarchy of the changes at genetic and molecular level including several aspects which are heterogenous and represents a wide spectrum such as tumor suppressor genes, oncogenes, cellcycle regulators, apoptosis, cell-adhesion molecules, loss of heterozygosity, microsatellite instability, and epigenetic changes. The classification of gastric carcinoma at molecular and genetic level as well as hereditary gastric carcinoma is elaborated. The molecular genetic aspects regarding pathogenesis, changes and aberrations of all genes and pathways which are involved in gastric cancer are addressed in this review.