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Detection Of Human Papillomavirus Infection By Hybridization Test In Prostate Biopsies. By Dr.Turky Al- Mouhissen Urology Chief Resident at Western Region, KKNGH – Jeddah Dr. Faten S. Gazzaz Virology Consultant, KAAUH, Jeddah
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Detection Of Human Papillomavirus Infection By Hybridization Test In Prostate Biopsies By Dr.Turky Al-Mouhissen Urology Chief Resident at Western Region, KKNGH – Jeddah Dr. Faten S. Gazzaz Virology Consultant, KAAUH, Jeddah Prof. Hisham A. MosliChairman of Saudi Urology Association, Professor of Urology, KAAUH, Jed.
Introduction • The American Cancer Society estimates that 18% of cancers worldwide are caused by infectious agents • The cause-effect relationship of infection or inflammation with prostate cancer has been suggested but not yet firmly established. • Many authors suggested that infection in the form of acute or chronic bacterial prostatitis may be associated with prostate cancer
Prostate cancer is one of the most common malignancies in males, but little is known about the molecular events involved in its development • The prostate could constitute a target for infection with Human Papillomavirus (HPV) due to anatomical reasons, particularly by direct access of viral particles through the urethra Human papillomavirus particles
Adam et al 2003 has suggested a relation between HPV infections and prostate cancer • Karodi et al 2005 criticized some studies that reported an association between HPV infections and prostate cancer • In a very recent paper, Al Moustafaproposed that HPV infections play an important role in the progression of prostate cancer
Infection with HPV is causally linked to the development of 99,8% of cervical cancer • In some recent studies, association were observed between prostate cancer and HPV • Moreover, prostate cancer does not meet some expected features of HPV-caused cancers • Prostate cancer is not squamous cell in origin • Does not occur at anatomic sites of exposure by direct contact
There comes the question in our study, as some studies show evidences of relation between HPV & prostate Ca • Only 2 of 20 investigations found an association between tissue evidence of prior HPV and prostate cancer • Many of the studies were limited by small sample size and used different methods for detection of HPV • They also suggest the lack of persistence of HPV antibodies is responsible for the difference in results between studies
A meta analysis provided evidence of a higher rate of prostate cancer in men with a h/o a exposure to gonorrhea, HPV or any STD • Substantial epidemiological evidence suggests that prostate cancer may also be initiated or promoted by other microbial infections
Patients and Methods • In our study, Digene’s HC2 HPV DNA test was used for HPV infection detection during period (march 2007 - December 2008) • A total of 56 male patients (n=56), range of age 50-93 years, diagnosed as having prostate cancer or BPH • The subjects of this study were men who attend the KAAU Hospital in Jeddah for • prostate biopsy due to suspected diagnosis of prostate cancer • patients going for TURP
Standard 12 cores TRUS Biopsies were obtained by Urology team for suspected prostate cancer • Additional biopsy was taken from the most suspected area of cancer to be included in our study • Also, patients going for TURP, one of the prostatic chips collected to be included in our study • Specimens included in the study were placed immediately into the Specimen Transport Media and transferred to the Virology laboratory at KAAUH to be stored at -20 degree C
The prostatic biopsies were processed to HPV DNA HC2 Digene test in the Virology lab • The HPV DNA tests using HC2 technology are signal amplified hybridization antibody capture Microplate assays that utilize chemiluminescent detection of 18 types of HPV DNA in prostatic specimens
1. Release and denature nucleic acids Clinical specimens are combined with a base solution which disrupts the virus or bacteria andreleases target DNA. No special specimen preparation is necessary. 2. Hybridize RNA probe with target DNA Target DNA combines with specific RNA probes creating RNA: DNA hybrids. 3. Capture RNA/DNA hybrids onto a solid phase Multiple RNA: DNA hybrids are captured onto a solid phase coated with universal capture antibodies specific for RNA: DNA hybrids. 4. React captured hybrids with multiple antibody conjugates Label for detection: Captured RNA: DNA hybrids are detected with multiple antibodies conjugated to alkaline phosphatase. Resulting signal can be amplified to at least 3000-fold. 5. Detect amplified chemiluminescent signal The bound alkaline phosphatase is detected with a chemiluminescent dioxetane substrate. Upon cleavage by alkaline phosphatase, the substrate produces light that is measured on Luminometer in relative light units (RLUs). The Basic Steps Of The Hybrid Capture Assay.
Results • A total of 56 prostatic specimens were included in the current study by HC2 • All prostatic lesions were categorized into • BPH • Malignant • Various inflammatory disorders • No HPV was detected among the 56 tested biopsies by using the HC2 (0%)
Patients Categories According Histological Results . (Total n=56)
Discussion • The possible etiologic role of HPV in prostate cancer is an active focus of research • Our study was conducted to assess the potential role of HPV in relation to risk of prostate cancer • In the analyzed collected prostate tissues, we have not detected any relationship between HPV DNA positivity and prostate adenocarcinoma, BPH, and BPH with inflammatory changes
Other studies have reported a positive association between serological evidence of HPV and prostate cancer • There were concerns about methodology & limited study size • Dependence on serological data to conclude any relationship between HPV & prostate cancer is not accurate, as HPV DNA in these studies were not studied
Kulamala et al 2004 & Gazzaz 2008 concluded that PCR test is not as sensitive for screening HPV as Hybrid Capture does • Meanwhile all investigators supporting the relation of HPV and prostate ca used PCR or HPV antibody detection
Reports of low incidence rate of Prostate Cancer in Saudi Arabia are well documented • The real reason behind this low incidence may be due to • ? Small cancer pool since population is young • ? Genetic make up of Saudi’s mostly Asian with low penetration of prostate cancer genes • ? Dietary intake devoid of pork • ? Consumption of protective Mediterranean diet • ? Role of circumcision at early neonatal life • ? Low prevalence of STD, chronic atrophic prostatitis, and viral infection
Our study did not find any association between the presence of HPV & histological inflammation in the prostate • These viruses are therefore unlikely to be considered as triggering factors of chronic prostate inflammation or the subsequent prostate cancer development
Conclusion • HPV infections is not one of the causes of prostate cancer or BPH in our community • The religious, moral and ethical behaviors that are associated with neonatal circumcision seems to protect the adult male in our local community from STD, bacterial & viral infections • Data from our research center at KAUH in Jeddah indicated absence of HPV DNA in several samples of prostatic tissues
Recommendations • We recommend further studies of the relationship of circumcision, STD and prostate cancer in a larger population to examine and confirm the protective role of circumcision against prostate cancer • Cases with h/o multiple STD, selected from populations in which STD is endemic, might result in the identification of a novel, sexually transmitted, prostate cancer agent