HHV-6 detectable in some urine samples, but not linked to disease

In contrast, human papillomavirus found more often in urine of bladder cancer patients than in urine of patients with non-cancerous urinary tract conditions

HHV-6 may be present in cells of the urinary tract, and shed in the urine, but was not found at elevated levels in patients with bladder cancer compared to controls. This was the conclusion of a study of the human urinary tract virome by a group from Charles University in Prague. The team examined the presence of multiple DNA viruses in the urine of people undergoing endoscopic procedures for benign or malignant conditions of the urinary tract. The study excluded people with evidence of low-grade bacterial urinary tract infections or any foreign body in the urinary tract.

In all, sterile catheterized urine specimens from 57 cases of bladder cancer and 49 controls with non-malignant urinary tract conditions were studied. Viral DNA was detected using real-time PCR technology (qPCR).  Fluorescent 5 6-FAM/3 BHQ-1 DNA probes were used. Reactions were performed with HotStart Taq Polymerase (Qiagen, Germany) on the Biorad CFX96 Real-Time PCR system (Biorad Laboratories, California, USA). Statistical comparisons of the prevalence of different viruses in malignant cases vs. non-malignant controls were adjusted for age and gender.

The frequency with which different DNA viruses were found in the urine of either cases or controls is as follows: JC polyomavirus, 47.6%; torque teno virus, 44.2%; BK polyomavirus, 15.5%; human papillomavirus (HPV), 15.2%; human herpesvirus-6, 12.5%; Epstein-Barr virus, 6.0%; and human cytomegalo­virus, 2.0%.  No adenoviruses, herpes simplex virus 1 and 2, or parvoviruses were found.

After adjustment for age and gender, only HPV was found to have significantly higher positivity rates in cases vs. controls (P=0.03) (Table).

Some previous studies also have found an association between HPV and bladder cancer, although others have not.  HPV is a well-established oncovirus, having been linked to cancers of the cervix, anus, oropharynx, penis, vagina and vulva. Linkage of the virus to multiple cancers of the urogenital tract makes it a plausible cause of some cases of bladder cancer.  However, this study is small, did not examine malignant bladder tissue and did not evaluate whether the viral signal detected in the urine came from bladder cells or white blood cells.  So the association it reports can only be regarded as provocative.

Read the full article: Hrbáček 2023