p53 Gene mutations in sporadic colorectal carcinoma in Guangxi region

To explore the spectrum of p53 gene mutations of sporadic colorectal carcinoma in Guangxi, a Zhuang autonomous region in southern China, we examined exons 2 approximately 11 and exon-intron junctions of p53 gene from 48 patients with sporadic colorectal carcinoma by using single strand conformation polymorphism (SSCP) and DNA direct sequencing. As a result, p53 gene mutations were found in 31.25 percent (15/48) of our patients. A total of 13 types of p53 gene mutations were found, namely, c.370T > G, c.524G > A, c.528C > G, c.529_546del18, c.536A > G, c.736A > G, c.743G > A, c.770_771del2, c.772G > T, c.814G > A, c.949delC, c.782+1G > A, and c.919+1G > C. Only a double heterozygote for c.370T > G and c.529_546del18 was found. All the other mutations were heterozygous. No homozygote was found. 524G > A was the most common mutation, accounting for 18.75 percent (3/16). c.370T > G could not be found in the whole somatic mutation section of IARC TP 53 mutation database (2004 version). c.528C > G, c.949delC, c.782+1G > A, and c.919+1G > C could not be found in colorectal carcinomas reported in the somatic mutation section of IARC TP 53 mutation database (2004 version). The frequency (45.83 percent) of p53 gene mutations in > or = 60 years old patients was higher than that (16.67 percent) in < 60 year old patients (P < 0.05). The frequency (47.83 percent) of p53 gene mutations in rectal carcinoma was higher than that (16 percent) in colonic carcinoma (P < 0.025).