title: Coexistence of K-ras mutations and HPV infection in colon cancer.
abstract: BACKGROUND
  Activation of the ras genes or association with human papillomavirus infection have been extensively studied in colorectal cancer. However, the correlation between K-ras mutations and HPV in colorectal cancer has not been investigated yet. In this study we aimed to investigate the presence of K-ras mutations and their correlation with HPV infection in colon cancer.
  
  
  METHODS
  K-ras mutations were analyzed by a mutagenic PCR assay and digestion with specific restriction enzymes to distinguish the wild-type and mutant codons. HPV infection was analyzed by PCR amplification and hybridization with specific probes by Southern blotting. Statistical analyses were performed by the chi-square and Fisher's exact tests
  
  
  RESULTS
  HPV gene fragments were detected in 43 tumors and 17 normal tissue samples. HPV 18 was the prevalent type in the tumor tissue. A mutation at codon 12 of the K-ras gene was present in 31 patients. 56% of the HPV-positive tumors also harbored a K-ras mutation. Codon 13 mutations were not observed. These data indicate that infection with high risk HPV types and mutational activation of the K-ras gene are frequent events in colorectal carcinogenesis.
  
  
  CONCLUSIONS
  Our findings suggest that mutational activation of the K-ras gene is a common event in colon carcinogenesis and that HPV infection may represent an important factor in the development of the premalignant lesions leading to the neoplastic phenotype.
authors: Department of Medical Biology, Cerrahpasa Medical Faculty, Istanbul University, Istanbul, Turkey. nbuyru@yahoo.com
authors: Nur
authors: N
authors: Buyru
authors: Ayda
authors: A
authors: Tezol
authors: Nejat
authors: N
authors: Dalay