In a total of 42 xenografted lung carcinomas studied, 45% amplification and 77% overexpression of one of the myc genes were detected with a high prevalence of L-myc overexpression in NE carcinomas (50%) and of c-myc overexpression in non-small cell lung carcinomas (66%).
Amplification of the c-myc gene was observed in 5 cell lines derived from well-differentiated carcinomas and all of them were accompanied by co-amplification of other examined oncogenes.
The rs6983267 SNP may contribute to the increased MYC expression as well as the spread and rapid growth of cervical SCC as compared to lower grade carcinomas.
To evaluate both the incidence of c-myc gene mutation and the relationship of this finding to the clinico-pathologic characteristics of patients with cervical cancer, a polymerase chain reaction (PCR)-based heteroduplex gel electrophoresis method was used to screen DNA extracted from 102 cervical invasive carcinomas referred to the Department of Obstetrics and Gynaecology, The Chinese University of Hong Kong.
High MYC amplification was seen in grade III carcinomas (MYC: CEP8 = 2.42), pre-menopausal women (MYC: CEP8 = 2.49), PR-negative status (MYC: CEP8 = 2.42), and ER-positive status (MYC: CEP8 = 2.4).
The UG/MYC transgenics will be useful to investigate the biochemical mechanisms underlying the development of carcinomas and the oncogenic properties of c-MYC in epithelial cells of various tissues.
Notably, switching off the oncogene in advanced carcinomas revealed that MYC was required for the continuous activation and repression of distinct sets of genes, constituting no more than half of all genes deregulated during tumor progression and an even smaller subset of all MYC-bound genes.
We investigated genomic amplification on chromosomes 7 and 8 by comparative genomic hybridization (CGH) and protein expression of relevant oncogenes (EGFR, HGF, MET, CTSB, MYC) by immunohistochemistry (IHC) in 22 esophageal and 22 gastric cardia carcinomas.
The overall frequency of gene amplification among the gastric carcinomas rose to 19.4% when MYC, ERBB2, and INT2 were included in the analysis, with significant association with advanced tumor stage.
In addition, the expression levels of Mina53 and c-Myc protein in gastric carcinomas were higher when compared with levels in the adjacent normal epithelium. mina53 expression was significantly increased during gastric carcinogenesis and was correlated with different clinicopathological factors in IGC and DGC.
Although the c-myc gene is overexpressed in approximately 70% of human colonic cancers, previous studies have not detected frequent gene amplification or rearrangement of c-myc in these tumors, although such amplification has been reported in chemically induced rodent colon cancer and quantitative analysis of gene copy number has shown the gene to be amplified at a low level in mucinous and poorly differentiated human colon carcinomas.
The TRPS1 and MYC expression levels were similar in all prostate tumour groups, whereas EIF3S3 expression was higher (P=0.029) in prostate carcinomas compared to BPH.