Distinctive clinicopathological features of Ki-ras mutated colorectal cancers.
OBJECTIVE
We explored the relationship between the mutation pattern of Ki-ras and the clinicopathological features of colorectal cancers (CRCs).


METHODS
Relationships between clinicopathological parameters and Ki-ras mutation status were analyzed in 255 CRC patients using the chi-square and student t-tests. Kaplan-Meier survival curves were compared using the log-rank test.


RESULTS
Ki-ras mutation occurred in 43.9% of tumors, and 83% affected codon 12. The most frequent mutations were GGT->GAT (Gly->Asp) (37.5%), followed by GGT->GTT (Gly->Val) (31.3%), both in codon 12. The frequency of Ki-ras mutation was similar for different tumor stages (38.2-47.8%). The mucin component of tumors was significantly associated with Ki-ras mutation. The 4-year overall and disease-free survival was 61% and 54%, respectively, for patients with Ki-ras mutated tumors, and 73% and 60% for patients with nonmutated tumors (not statistically significant). Patients with Ki-ras mutated tumors had lower plasma folate (24 ng/dl) than those bearing nonmutated tumors (37 ng/dl). Patients with G->T Ki-ras mutations had the lowest folate level (22 ng/dl), followed by those with G->A mutations (25 ng/dl).


CONCLUSIONS
Ki-ras mutated colorectal tumors have a higher mucin production and higher differentiation, and are associated with lower plasma folate levels and a relatively poorer disease outcome.
Lin
Jen-Kou
JK
Division of Colon & Rectal Surgery, Department of Surgery, Taipei Veterans General Hospital, National Yang-Ming University, Taipei, Taiwan. jklin@vghtpe.gov.tw
Chang
Shih-Ching
SC
Wang
Huann-Sheng
HS
Yang
Shung-Haur
SH
Jiang
Jeng-Kai
JK
Chen
Wei-Chone
WC
Lin
Tzu-Chen
TC
Li
Anna Fen-Yau
AF
D000368:Aged; D002118:Calcium / Q000097:blood; D016009:Chi-Square Distribution; D015179:Colorectal Neoplasms / Q000097:blood / Q000235:genetics* / Q000473:pathology*; D004252:DNA Mutational Analysis; D005260:Female; D005492:Folic Acid / Q000097:blood; D005787:Gene Frequency / Q000235:genetics; D011905:Genes, ras / Q000235:genetics*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009154:Mutation; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D011379:Prognosis
D005492:Folic Acid; D002118:Calcium