Clinicopathologic significance of the K-ras gene codon 12 point mutation in stomach cancer. An analysis of 140 cases.
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Lee KH, Lee JS, Suh C, Kim SW, Kim SB, Lee JH, Lee MS, Park MY, Sun HS, Kim SH
Clinicopathologic significance of the K-ras gene codon 12 point mutation in stomach cancer. An analysis of 140 cases.
Cancer. 1995 Jun 15;75(12):2794-801.
- PubMed ID
- 7773929 [ View in PubMed]
- Abstract
BACKGROUND: The frequency and clinicopathologic significance of the K-ras gene point mutation in stomach cancer remain to be defined. METHODS: The authors investigated the frequency of K-ras codon 12 point mutations in stomach cancer using a sensitive polymerase chain reaction (PCR)-based method in 140 samples and correlated the findings with various clinicopathologic characteristics of the patients. RESULTS: The overall frequency of K-ras codon 12 point mutations in stomach cancer was 7.9% (11/140). DNA sequencing of nine cases with K-ras codon 12 point mutations identified seven cases with a single-base substitution of GGT to AGT (glycine to serine) and two with single-base substitution of GGT to AGT (aspartic acid). Tumors located in the upper third of the stomach had a significantly higher frequency of K-ras codon 12 mutations (3/8, 37.5%) compared with tumors located in the middle (4/29, 13.8%) or lower (3/99, 3.0%) thirds of the stomach (P = 0.001). No significant difference was observed in the frequency of K-ras codon 12 mutations in terms of other various clinicopathologic characteristics including tumor DNA ploidy and S-phase fraction. After a median follow-up of 26 months, disease free and overall survival were not significantly different between patients with stomach cancer with or without K-ras codon 12 mutation. Among eight patients with stomach cancer located in the upper part of the stomach, none of the three patients with K-ras gene-mutated tumors died versus four of five with tumors without K-ras gene mutations (P = 0.064). CONCLUSIONS: K-ras codon 12 point mutations are uncommon in stomach cancer (7.9%). There was significant correlation between K-ras mutations and vertical tumor location in the stomach, suggesting that different mechanisms may play a role in the pathogenesis of stomach cancer according to the location of tumors in the stomach.