Frequency of BK virus genotypes in patients with colorectal cancer

Abstract

Background and objectives: BK polyomavirus infection is prevalent and primarily asymptomatic, except for complications in kidney transplant recipients. Furthermore, its involvement in a tumorigenic family necessitates consideration in various malignancies such as urogenital tumors, prostate cancer, colorectal cancer (CRC), and brain cancer.

Materials and methods: This investigation encompassed 50 specimens of colorectal adenocarcinoma tumors, 50 adjacent tissues, and 40 urine samples, with patients having a mean age of 61 years ± 12.4 years. The detection of BK virus DNA VP1 gene and genotyping were carried out through nested-PCR and sequencing techniques.

Results: Through the utilization of nested-PCR, BK virus DNA was identified in 15/50 (30%) colorectal tumor samples and 3/50 (6%) adjacent tissues (p-value = 0.008). Additionally, 6/40 (15%) urine samples exhibited positive results for BK virus DNA. Notably, among these findings, 9/15 BK virus positive tumor tissues (60%) and 3/6 BK virus positive urine samples (50%) were confirmed to be positive for BK virus subtype 4 (p-value < 0.001), whereas 2 tumor samples and 3 urine samples were attributed to BK virus type 1b2.

Conclusion: It is imperative to enhance one's understanding of the etiological and risk factors pertaining to cancers. The present findings offer substantiation of a potential correlation between BK virus infection and colorectal cancer. BK virus genotype 4 was found to be dominant among the CRC patients in this study.

Keywords: BK polyomavirus; Colorectal cancer; Genotypes; Urine.

Fig. 1.

The phylogenic tree was constructed by Maximum Likelihood Method for VP1 sequences BK virus genome isolates from CRC patients. The phylogenetic tree results indicated that the BK virus isolated from Ahvaz (OR064035-OR064044) clustered with genotype IV, JN794001.1 and MK647972.1 which were isolated in France. The BK virus isolated from Ahvaz (OR113380-OR113383) were cluster with BK genotype 1a MH647646, MH647646, MH647648, KC412462, KC412463 which were isolated from Brazil. An interesting thing was a male CRC patient tumor sample, OR064041 which identified as BK virus genotype 4, while his urine OR113383 was BKV genotype 1. The Tamura-Nei model was employed for the Maximum Likelihood method with 1000 bootstrap replicates. The scale bar was set at 0.01.