Infrequent somatic mutations of the p73 gene in various human cancers
1Department of Molecular Pathology, Tohoku University School of Medicine, Sendai, Japan.
Aims:
It has already been reported that loss of heterozygosity (LOH) on chromosome 1p is frequent in a variety of human cancers. This finding implies the presence of some important tumour suppressor genes in this region. p73, a candidate tumour suppressor gene identified recently in chromosome band 1p36.33, encodes a protein highly homologous to p53. To investigate the role of the p73 gene in human carcinogenesis, we studied genetic alterations of this gene in various human cancers.
Methods:
We analysed the entire coding exons as well as their surrounding exon-intron boundaries of the p73 gene in 185 cases of various types of tumours (47 breast cancers, 43 colorectal cancers, 31 gastric cancers, 23 neuroblastomas, 21 lung cancer cell lines, and 20 pancreatic cancer cell lines); they are known as a group of tumours with frequent LOHs in the 1p region. PCR-SSCP analysis was performed and tumours in which aberrant migrating sized bands were observed were subjected to direct sequencing analyses.
Results:
Of the 185 cases, only one somatic mis-sense mutation of glutamine from arginine at codon 269 in exon 7 was found in one breast cancer. In addition, several polymorphisms were found at codons 137, 336, 349, and 610, as well as in introns 6, 8, and 9. Monoallelic expression was also observed in pancreatic cancer cell lines.
Conclusions:
Our results suggest that inactivation of the p73 gene does not play a major role in the tumour types analysed in the present study.
Related Concept Videos
Mutations
Abnormal Proliferation
Cancers Originate from Somatic Mutations in a Single Cell
Loss of Tumor Suppressor Gene Functions
When the tumor suppressor genes develop mutations or are lost, cells start growing out of control, leading to cancer. However, a single functional copy of the tumor suppressor gene is enough for the cells to maintain their normal functions and cell...
Cancer-Critical Genes II: Tumor Suppressor Genes
When the function of certain critical genes, especially those involved in cell cycle regulation and cell growth signaling cascades, gets disrupted, it upsets the cell cycle progression. Such cells with unchecked cell cycles start proliferating uncontrollably and eventually develop into tumors.
Such genes that act...
Cancers Originate from Somatic Mutations in a Single Cell


