Abstract
Relevance: Colorectal cancer (CRC), arising from the right-sided or left-sided colon, is a separate clinical and pathological unit. The status of KRAS and its predictive value in CRC remain controversial. The study aimed to explore the effect of primary tumor localization on KRAS gene status in CRC. Methods: The study included 60 patients with colon and rectal cancer. The KRAS mutation test was performed on paraffin-coated tumor samples using PCR methods. Colon cancer was divided into right-sided colon cancer (RSCC) and left-sided colon cancer (LSCC). Results: KRAS mutation was found much more often in rectal cancer (RC) and sigmoid colon (SC) (p=0.413) than in tumors in other parts of the colon. A combined analysis of our data and previously published data showed that KRAS mutation was more common in PSTC, especially in the area of the hepatic bend of the colon than in LSTC (p=0.120). The association of the KRAS mutation with the patient’s age (p<0.012) and the duration of hospitalization (p<0.001) was established. Conclusion: Our study revealed no significant difference in the KRAS status between colon cancer and rectal cancer. However, KRAS mutation was much more common in RSCC compared to LSCC. Patients with RSCC with mutated KRAS also had a worse prognosis and required longer hospitalization compared to wild-type KRAS. However, patients with LSCC did not demonstrate a similar effect.