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 notdetected 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.

Does human papillomavirus cause human colorectal cancer? Applying Bradford Hill criteria postulates

“…The positivity ratio of HPV detection in CRC samples was varied population wise from 0% [ 11 , 12 , 17 , 23 , 26 , 32 , 41 , 43 , 45 , 46 , 50 , 59 ] to 100% [ 13 , 54 ] in all the 59 studies, whereas the positivity ratio of HPV detection in normal and adjacent/benign samples was varied from 0% [ 21 , 22 , 29 , 30 , 43 , 49 ] to 84% (28) and 0% [ 17 , 22 , 26 , 41 , 42 , 45 , 46 , 50 , 52 , 57 ] to 69.56% [ 54 ], respectively.…”

Human papillomavirus infection and colorectal cancer in the Chinese population: a meta‐analysis

“…reported HPV infection only in rectal cancer together with the highest HPV infection rate (71%) in all studies [22]. With respect to the site of cancer, a higher pooled OR was founded in rectal cancer.…”

“…Twelve papers that contained no relevant information were also excluded. Ten papers were included in the final meta-analysis [20][21][22][23][24][25][26][27][28][29].…”

Factors affecting sphincter-preserving resection treatment for patients with low rectal cancer

“…The increase in surgical difficulty as a result of obesity may decrease the rate of sphincter preservation in patients from the Uygur ethnicity (36,37). Furthermore, on an economical and cognitive level, rectal cancer in Uygur populations is generally diagnosed much later in the disease stage, resulting in a larger tumor size and deeper invasion, which greatly influences the rate of sphincter preservation (38)(39)(40). In the present study, univariate analysis demonstrated that the sphincter-preserving factor was significantly associated with gender, BMI, age and tumor grade.…”