Relevance of urine analysis for HPV as a screening method for preventing and detecting precancerous and cancerous conditions of the cervix

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Introduction. Cervical cancer is a serious problem worldwide, being one of the leading causes of death among women. About 500,000 new cases are registered annually, with the majority of them occurring in developing countries [1]. Most cases of this type of cancer are associated with persistent human papillomavirus (HPV) infection, which is predominantly sexually transmitted. HPV is responsible for 4.5% (630,000) of new cases of cancer of all localizations. Currently, more than 200 HPV genotypes are known, of which 16, 18, 31, 33, 33, 35, 39, 45, 51, 52, 56, 58 and 59 types are among the highly oncogenic strains that most often lead to the development of cervical intraepithelial lesions.
The increasing incidence of precancerous and cancerous conditions of the cervix, as well as increasing mortality rates, require active sensitization of women about the importance of regular gynecologic examinations. The introduction of screening programs helps to move closer to the goal of cervical cancer elimination. However, diagnosis of tumors is complicated by the fact that many women do not visit obstetrician-gynecologists. Therefore, affordable laboratory methods of urine HPV testing are being developed for early detection of cervical lesions. This approach allows to conduct the examination conveniently and inexpensively, without the need to visit a doctor [2, 3, 4].

Materials and Methods of the Study. The study, conducted at VGKP №1 of the Ministry of Health of the Russian Federation, was aimed at evaluating the feasibility of using urine HPV testing as a screening test for detecting cervical intraepithelial lesions.
The study compared the results of cervical and cervical smears with the results of the first urine sample for HPV. The percentage concordance, overlap, and discrepancy of virus types and concentrations between the two assays were determined. Additionally, the incidence of abnormalities on colposcopy and pathologic changes on cytologic examination with a positive urine HPV test was studied.

The study involved 30 female patients divided into two groups depending on the test system used for quantitative PCR analysis: group 1 - tested for HPV quantum 21, group 2 - for HPV quantum 15. The difference between the tests is the number of virus strains to be determined: quantum 15 determines two types of HPV of low (HPV 6, 11) and 13 types of high (HPV 16, 18, 31, 33, 35, 39, 39, 45, 51, 52, 52, 56, 58, 59, 68) oncogenic risk. Quantum 21 is the most detailed study in the lineup, including differentiation and DNA quantification of HPV of low oncogenic risk (HPV 6, 11, 44) and high (HPV 16, 18, 26, 26, 31, 33, 33, 35, 39, 39, 45, 45, 51, 52, 53, 56, 58, 59, 66, 68, 73, 82) [5].
The biomaterial was collected by the doctor of the cervical pathology office, associate professor of the N.N. Burdenko FGBOU VO VSMU of the Ministry of Health of Russia Khoperskaya O.V. Samples were taken from the surface of the exocervix and from the cervical canal using a special disposable cytobrush. The obtained material was placed in an eppendorf tube filled with a special transport medium for bioassays with a mucolytic (STOR-M). The transport medium contains a preservative that prevents the reproduction of foreign microorganisms and a mucolytic that helps liquefy mucus.

The biomaterial was analyzed in the laboratory of BUEZ VOH “VGKP №1”. After confirming the presence of HPV in the scrapings, women were offered to take a urine sample. For this purpose, the first morning urine sample of about 5-10 ml was used. 1.0 ml of the sample was transferred into a 1.5 ml plastic tube. Centrifugation of the tube was then performed at RCF(g) 12000 - 16000 for 10 minutes. The supernatant was then removed, 1.0 mL of sterile saline was added and the tube was centrifuged again under the same conditions. After removal of the supernatant, approximately 50 µl (precipitate + liquid fraction) was left.
DNA extraction was performed using the PROBA-GS-PLUS reagent kit.

First, a 50 µl tube with the prepared sample was labeled, and the vials with lysing solution and washing solution #1 were heated to 50°C for 15-20 minutes to dissolve the precipitate in them. A 1.5 mL tube was prepared for negative control smear (“K-”) where 50 μL of transport medium was added. In another tube, lysing solution and sorbent were mixed: 150x(N+1) µl of lysing solution and 20x(N+1) of pre-suspended sorbent particles, where N+1 is the total number of samples tested together with “K-”, plus one additional sample. 170 µl of the resulting mixture was added to each test tube. The test tubes were then thermostated at 50°C for 20 minutes. This was followed by triple centrifugation at RCF(g) 12000-16000 for one minute, successively removing the supernatant and adding 200 µl each of wash solutions #1, #2, #3. The lids of the tubes were opened to dry the precipitate at 50°C for five minutes and then centrifuged again. The supernatant with isolated DNA was added to the reaction mixture for PCR-amplification on the detection amplifier “DTlite” using test systems Kvant 15 and Kvant 21.

Study results. The results of the study allowed us to distinguish three subgroups: complete concordance of virus types in both tests, partial concordance, when some HPV strains found in the scrapings were also present in the urine, and inconsistency, when HPV was not detected in the urine. In the first group of patients, complete concordance was 22%, partial concordance was 45%, and inconsistency was 33% of the total number of patients. In the second group, partial concordance was observed in 25% of the patients, complete concordance in 33%, and inconsistency in 42%.
In both groups, there was an association between the presence of HPV DNA in the urine and high titers of the virus in the scrapings. Among group 1 patients with inconsistent results, the proportion of low titers (up to and including 3) was 58%, whereas the proportion of high titers (4 or more) was 42%, 60%, and 40%, respectively, in group 2 women.
In women who had partially detectable HPV DNA in urine, there was a correlation of excretion of the same virus types with high titers (4 or more) in both tests.
Patients in both groups, in whom the results of the tests coincided completely, had only high titers of the virus (4 or more).
Thus, it can be concluded that in women who showed a complete mismatch, HPV DNA was not excreted in the urine because low titers of virus were present in the scrapings.

A comparative analysis of colposcopy and cytology results depending on the presence or absence of HPV DNA in urine was performed for both groups.
Of the 18 patients in whom HPV was detected in cervical material using the Quant-21 system, only 12 (66.66%) had HPV detected in urine using the same testing system. As for cervical specimens, abnormalities in colposcopic examination were detected in only 10 patients (55.55%). If we consider cases with positive urine HPV test results, an abnormal pattern was detected in 8 out of 12 patients, representing 66.66% - the sensitivity of diagnosis of colposcopic changes increased by 11.11% compared to HPV detection through cervical sampling.
In the first group of 18 HPV-positive cervical samples, abnormal cytologic findings (ASC-US, LSIL and HSIL) were established in 5 patients (27.77%). 4 abnormal cytologic specimens (80%), 2 of which ASC-US, 1 LSIL and 1 HSIL had both positive HPV tests.

The first group also had a high percentage of normal colposcopic pictures of 44.44%, which is 11.11% less frequent in HPV-positive urine samples.
In the second group, out of 12 HPV-positive samples taken from the surface of the exocervix and cervical canal, the virus in urine was detected in 58.33% of cases. On examination of cervical samples, abnormal colposcopic pattern was recorded in 6 patients (50%). Out of 7 positive urine tests, 4 (57.14%) also showed abnormality, making diagnosis by colposcopy 7.14% more effective in urine HPV positive cases.
Abnormal cytology was diagnosed in 3 (25%) patients from group 2. 2 (28.57%) patients out of 7 HPV positive by urine test had ASC-US and LSIL by oncocytology.
The percentage of normal colposcopic pictures in the second group of women was 50%, which was 7.15% higher than that of positive urine test.

Table 1. Comparison of results of Kvant 21 and Kvant 15 test systems

Test system	Kvant 21 (n=18)		Kvant 15 (n=12)
Biotope	Cervical scraping	First urine sample	Cervical scraping	First urine sample
+ status	18 (100%)	12 (66.66%)	12 (100%)	7 (58.33%)
AX	10 (55,55%)	8 (66,66%)	6 (50%)	4 (57,14%)
OC>ASCUS	5 (27,77%)	4 (33,33%)	3 (25%)	2 (28,57%)
NCX	8 (44,44%)	4 (33,33%)	6 (50%)	3 (42,85%)
NILM	13 (72,22%)	8 (66,66%)	7 (58,33%)	6 (85,7%)

Conclusion. Thus, the results showed an association between the presence of HPV DNA in urine and high concentrations of the virus in scrapings. The incidence of colposcopy abnormalities and oncocytology abnormalities in HPV-positive urine tests was significant. This confirms the prospect of using urine HPV testing as a possible screening method for the prevention and early detection of precancerous cervical conditions.

About the authors

Yuliana Andrianovna Lukina

Voronezh State Medical University named after N. N. Burdenko

Author for correspondence.
Email: ualukina@yandex.ru
ORCID iD: 0009-0004-8807-3737

Student 

Russian Federation, 10 Studencheskaya str., Voronezh, 394036, Russia

Olga Viktorovna Khoperskaya

Voronezh State Medical University named after N. N. Burdenko

Email: khoperskaya88@bk.ru
ORCID iD: 0000-0003-4199-8156
SPIN-code: 7721-5051

Candidate of Medical Sciences, Assistant of the Department of Obstetrics and Gynecology No. 2

Russian Federation, 10 Studencheskaya str., Voronezh, 394036, Russia

References

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