title: Significance of HPV infection and genic mutation of APC and K-ras in patients with rectal cancer.
abstract: BACKGROUND
  Significance of HPV infection and genic mutation of APC and K-ras in rectal cancer has been investigated but not clarified. The objective of our study was to investigate these parameters in patients with rectal cancer to analyze correlations with biological behaviour, to determine relationships among the three, and also to demonstrate survival prognosis effects.
  
  
  METHODS
  From December 2007 to September 2008, 75 rectal cancer cases confirmed by histopathology in the Tumor Hospital of Xinjiang Medical University were enrolled. The control group consisted of normal rectal mucous membrane taken simultaneously, a least 10 cm distant from the carcinoma fringe. HPV DNA, the MCR of APC and exon-1 of K-ras were detected by PCR and PCR-SSCP. All results were analyzed in relation to clinical pathological material, using chi-square and correlation analysis via SPSS.13 and Fisher's Exact Probability via STATA. 9.0. All 75 patients were followed up for survival analysis using Kaplan-Meier and Log-rank tests.
  
  
  RESULTS
  55 out of 75 cases demonstrated gene HPV L1 while it was not detected in normal rectal mucosa tissue. HPV infection was correlated with age and lymphatic metastasis (P<0.05) but not other characteristics, such as ethnicity, tumor size, histological type, tumor type, Duke's stage and infiltration depth. Some 43 cases exhibited APC genic mutation (57.3%) and 34 K-ras genic mutation (45.3%). APC genic mutation was correlated with gender( P<0.05), but not age, histological type, infiltration depth, lymphatic metastasis and Duke's stage. In 55 cases of rectal cancer with HPV infection, there were 31 cases with genic mutation of APC (56.4%) and 24 with genic mutation of K-ras (43.6%). For the 20 cases of rectal cancer with non-HPV infection, the figures were 12 cases (60%) and 10 (50.0%), respectively, with no significant relation. Survival analysis showed no statistical significance for K-ras genic mutation, APC genic mutation or HPV infection (P>0.05). However, the survival time of the patients with HPV infection was a little shorter than in cases without HPV infection.
  
  
  CONCLUSIONS
  Our results suggest that HPV infection might be an important factor to bring about malignant phenotype of rectal cancer and influence prognosis. Genic mutation of APC and K-ras might be common early molecular events of rectal cancer, but without prognostic effects on medium-term or early stage patients with rectal cancer.
authors.affiliation: Deparment of Abdomen Surgery, Affiliated Tumor Hospital, Xinjiang Medical University, Urumqi, China.
authors.forename: Zhen-Qiang
authors.initials: ZQ
authors.lastname: Sun
authors.forename: Hai-Jiang
authors.initials: HJ
authors.lastname: Wang
authors.forename: Ze-Liang
authors.initials: ZL
authors.lastname: Zhao
authors.forename: Qi-San
authors.initials: QS
authors.lastname: Wang
authors.forename: Chuan-Wen
authors.initials: CW
authors.lastname: Fan
authors.forename: Fa
authors.initials: F
authors.lastname: Fang
mesh_terms: D000328:Adult; D000368:Aged; D036022:Capsid Proteins / Q000378:metabolism; D002277:Carcinoma / Q000209:etiology* / Q000378:metabolism / Q000556:secondary; D016009:Chi-Square Distribution; D004279:DNA, Viral / Q000378:metabolism; D018572:Disease-Free Survival; D005091:Exons; D005260:Female; D017491:Genes, APC; D011905:Genes, ras / Q000235:genetics*; D006801:Humans; D053208:Kaplan-Meier Estimate; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009154:Mutation; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D009856:Oncogene Proteins, Viral / Q000378:metabolism; D030361:Papillomavirus Infections / Q000378:metabolism*; D012004:Rectal Neoplasms / Q000209:etiology* / Q000378:metabolism / Q000473:pathology
chemical_list: D036022:Capsid Proteins; D004279:DNA, Viral; C114580:HPV L1 protein, Human papillomavirus; D009856:Oncogene Proteins, Viral