Different genetic pathways to proximal and distal colorectal cancer influenced by sex-related factors

Int J Cancer. 1997 Dec 19;74(6):664-9. doi: 10.1002/(sici)1097-0215(19971219)74:6<664::aid-ijc18>3.0.co;2-5.


Mutations in the k-ras and TP53 genes, as well as microsatellite instability (MIN), are frequent genetic alterations in colorectal carcinomas and represent 3 different mechanisms in the carcinogenic process. Both the incidence of colorectal cancer and the frequency of genetic alterations in such tumours have been related to different clinico-pathological variables, including age and gender of the patient and location of the tumour. A number of studies have also reported associations between different types of genetic alterations. We therefore wanted to explore the relationship between these genetic and clinico-pathological variables using multivariate analysis on material from 282 colorectal carcinomas. Three logistic regression models were constructed: 1) the presence of K-ras mutations was dependent on MIN and age and gender of patient, with an especially low frequency among younger males and in tumours with MIN (overall p = 0.0003); 2) the presence of TP53 mutations was only dependent on tumour location, with a positive association to cancers occurring distally (p = 0.002); and 3) the presence of MIN was dependent on age, gender and K-ras and TP53 mutations, as well as on tumour location. MIN was most frequent among younger male and older female patients, was rare in tumours with K-ras or TP53 mutations and was found almost exclusively in the proximal colon (overall p < 0.0001). Our data confirm that different genetic pathways to colorectal cancer dominate in the proximal and distal segments of the bowel and suggest that the K-ras- and MIN-dependent pathways are influenced by different sex-related factors.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Colorectal Neoplasms / genetics*
  • Colorectal Neoplasms / pathology
  • DNA, Neoplasm / genetics
  • Female
  • Genes, p53
  • Genes, ras
  • Humans
  • Male
  • Microsatellite Repeats
  • Middle Aged
  • Mutation
  • Regression Analysis
  • Sex Factors


  • DNA, Neoplasm