c-myc overexpression is a tumor-specific phenomenon in a subset of human colorectal carcinomas.
The transcriptional activity of the c-myc proto-oncogene was examined in 25 primary human colorectal carcinomas and their corresponding normal mucosae. The purpose was to determine whether the elevated levels of c-myc expression, frequently detected in this type of tumor, might be the consequence of alterations in the cell growth rate or the effect of a real transcriptional deregulation of the gene. In about 44% of the tumors the elevated c-myc expression was consequent to the enhanced growth rate of the neoplastic tissue, as estimated by the expression of the S-phase-specific histone H3 gene. In the other 56%, c-myc overexpression did not entirely depend on the proliferative activity of the neoplastic population. In this latter group, c-myc deregulation did not reside in structural modifications of the putative regulatory regions of the gene. Therefore, c-myc overexpression, at least in a subset of colorectal cancer, seems to be consequent to alterations in transregulative phenomena exerted on the c-myc gene by other genetic loci.
Division of Experimental Oncology 1, Centro di Riferimento Oncologico, Aviano.
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Maestro
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Toffoli
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Grion
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Boiocchi
D000230:Adenocarcinoma / Q000235:genetics; D003106:Colon / Q000032:analysis; D015179:Colorectal Neoplasms / Q000235:genetics*; D005091:Exons; D015870:Gene Expression; D006801:Humans; D008745:Methylation; D000090063:Proto-Oncogene Mas; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D016271:Proto-Oncogene Proteins c-myc; D011519:Proto-Oncogenes; D012333:RNA, Messenger / Q000032:analysis; D014158:Transcription, Genetic
C000715470:MAS1 protein, human; D000090063:Proto-Oncogene Mas; D011518:Proto-Oncogene Proteins; D016271:Proto-Oncogene Proteins c-myc; D012333:RNA, Messenger