[KRAS gene mutation in colorectal cancer].

BACKGROUND

KRAS oncogene is involved in colorectal carcinogenesis in 22 to 45% of cases.

AIM

To determine the frequency, types and distribution of KRAS mutations in colorectal cancer.

MATERIAL AND METHODS

KRAS mutations studies were carried out in primary tumors and metastases of colo-rectal cancer from 56 women aged 60 ± 14 years and 53 men aged 61 ± 11 years. Formalin fixed and paraffin embedded tissue samples were evaluated using RFLP (Restriction Fragment Length Polymorphism) and direct sequencing.

RESULTS

Primary tumors were located in the colon and rectum in 82 (75.2%) and 24 cases (20%), respectively. In three cases the extraction site of the tumor sample was unknown. In 46 cases (42.2%) KRAS mutations were demonstrated. The main point mutations were located in codon 12 (80.4%), G12D (39.1%), G12V (24.2%), G12S (6.5%), G12A (4.3%); G12C (4.3%), G12R (2.1%) and 19.6% at codon 13 (G13D). No differences were demonstrated in the frequency and distribution of mutations by gender, age, primary versus metastatic tumors or tumor location.

CONCLUSIONS

In this series, 42% of colorectal cancer tissue samples had KRAS mutations. Their frequency and distribution are similar to those reported in the literature, except for G12C mutation.