Prevalence of JC Virus in Chinese Patients with Colorectal Cancer

Abstract

BackgroundJCV is a DNA polyomavirus very well adapted to humans. Although JCV DNA has been detected in colorectal cancers (CRC), the association between JCV and CRC remains controversial. In China, the presence of JCV infection in CRC patients has not been reported. Here, we investigated JCV infection and viral DNA load in Chinese CRC patients and to determine whether the JCV DNA in peripheral blood (PB) can be used as a diagnostic marker for JCV-related CRC.Methodology/Principal FindingsTumor tissues, non-cancerous tumor-adjacent tissues and PB samples were collected from 137 CRC patients. In addition, 80 normal colorectal tissue samples from patients without CRC and PB samples from 100 healthy volunteers were also harvested as controls. JCV DNA was detected by nested PCR and glass slide-based dot blotting. Viral DNA load of positive samples were determined by quantitative real-time PCR. JCV DNA was detected in 40.9% (56/137) of CRC tissues at a viral load of 49.1 to 10.3×104 copies/µg DNA. Thirty-four (24.5%) non-cancerous colorectal tissues (192.9 to 4.4×103 copies/µg DNA) and 25 (18.2%) PB samples (81.3 to 4.9×103 copies/µg DNA) from CRC patients were positive for JCV. Tumor tissues had higher levels of JCV than non-cancerous tissues (P = 0.003) or PB samples (P<0.001). No correlation between the presence of JCV and demographic or medical characteristics was observed. The JCV prevalence in PB samples was significantly associated with the JCV status in tissue samples (P<0.001). Eleven (13.8%) normal colorectal tissues and seven (7.0%) PB samples from healthy donors were positive for JCV.Conclusions/SignificanceJCV infection is frequently present in colorectal tumor tissues of CRC patients. Although the association between JCV presence in PB samples and JCV status in tissue samples was identified in this study, whether PB JCV detection can serve as a marker for JCV status of CRC requires further study.

Viral infections and colorectal cancer: A systematic review of epidemiological studies

“…With the exception of two large studies that examined blood samples from 729 and 386 patients, respectively, numbers of patients were generally low (median = 69). Among four studies comparing JCV DNA between tumor and adjacent noncancerous tissues, two studies reported a significantly higher prevalence of the virus in tumor tissues . In addition, Coelho et al also detected JCV DNA between 100 colorectal lesions (hyperplastic polyps, adenomas and adenocarcinomas) and 100 adjacent normal colorectal mucosae, which reported a significantly higher prevalence in colorectal lesions than normal controls (90% vs .…”

“…Among three studies comparing seroprevelance of JCV between CRC cases and healthy controls, only one study by Mou et al in 2012 reported significantly elevated prevalence of JCV in CRC patients as compared with healthy controls (OR: 3.0, 95% CI :1.2–8.5). Besides, Mou et al also found a higher JCV prevalence in tissues of CRC patients when comparing to colorectal tissues from healthy controls (OR: 6.6, 95% CI: 2.9–14.9). However, a statistically difference of the JCV prevalence between CRC cases and healthy controls was not confirmed in any of the other studies.…”

“…In this review, we found that published epidemiological data on the association between on JCV and CRC are sparse. Most of the few studies reported to date had small sample sizes, and even though statistically significant associations were reported in some of them, results were inconsistent across studies . It was also observed that JCV was relatively common in healthy individuals reflecting the high seroprevalence of JCV infection in the general population, which has been estimated to range from 20 to 60% in countries from different parts of the world .…”

Significance of Infectious Agents in Colorectal Cancer Development

“…Adjacent normal mucosa in 35 positive colon adenocarcinoma specimens, and normal mucosa from six patients of the control group, had low viral loads 50-450 copies/µg DNA 76. Interestingly, PCR without adjustment with topoisomerase 77 showed statistically higher number of JCV copies in cancer than in non-cancerous tissues with a much higher relative number of copies/µg of DNA (49.1 to 10.3x10 4 in cancer tissue compared to 9-20x 10 3 in Theodoropoulos's study).…”

Advances and Prospects in Cancer Immunotherapy

“…An association between JC virus (JCV) and colorectal cancers (CRC) is known [175,176]. JCV encodes a gene expressing T-antigen, which is detected in the majority of CRC patients with positive family history [177].…”