Correlating p16INK4a /Ki-67 co-expression and gene methylation with HIV infection and high-risk HPV in abnormal cervical squamous intraepithelial cells

Date
2023-03
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Stellenbosch : Stellenbosch University
Abstract
ENGLISH SUMMARY: Globally, cervical cancer is the fourth most common cancer amongst women. Persistent infection with high-risk human papillomavirus (HPV) is shown as the causal factor in cervical cancer development. Women living with HIV is six times more prone to cervical cancer development. The aim of this study was to identify the HR-HPV types, investigate the simultaneous expression of p16INK4a and Ki-67 and evaluate the methylation status of CADM1, MAL and miR124-2 genes in cytology samples from HIV-positive and HIV-negative women with LSIL, HSIL, ASC-US, and ASC-H Pap smear results. Study participants were women between the ages of 21 years to 60 years referred to the Colposcopy clinic at Tygerberg Academic Hospital. Exfoliated cervical intraepithelial cells were collected in Surepath medium and HR-HPV types were determined using the Hybrispot HPV direct flow chip kit, whereas the co- expression of p16INK4a/Ki-67 proteins was evaluated with the CINtecĀ® Plus cytology immunocytochemistry kit. For methylation assays, DNA was isolated from the left-over exfoliated cells followed by the assessment of quantity and purity of isolated DNA using fluorometry and spectrophotometry, respectively. Isolated DNA was bisulfite converted and the methylation assays for the CADM 1, MAL and miR-124-2 genes were done using the respective EpiMelt assays. HPV DNA detection results were associated with cytological diagnosis as well as HIV status. In our study group 74 % (51/69; 95% CI: 62,1%-83%) of woman tested positive for HPV of which 70.6% (36/51) were of WLWH and 29.4% (15/51) of HIV negative women. Our results showed that p16INK4a /Ki-67 dual-staining was detected in 43.8% (25/57) of the samples with the HSIL cytology showing the highest p16INK4a /Ki-67 co-expression rate of 64% (16/25) compared to the other cytology groups. The proportion of the LSIL group with p16INK4a /Ki- 67 dual staining was 33,3% (4/12), whereas that of the ASC-US and ASC-H groups were 25% (2/8) and 23% (3/13) ASC-H, respectively. CADM1 methylation was detected in 12.3% (7/57) of samples, while MAL and the miR-124-2 genes showed methylation in 14% (8/57) and 12.3% (7/57)of the samples, respectively. HPV infection was detected in 28.1% (16/57) of the samples with methylated CADM1, MAL and miR-124-2 genes. A significant relationship was found between HR-HPV and miR-124-2 methylation. The logistic regression model analysis employing predictors such HR-HPV, p16INK4a and Ki- 67 co-expression, as well as the methylation status of the CADM1, MAL, and miR-124-2 genes, for LSIL cytology showed low sensitivity and high specificity, contrasting to that of the HSIL model with high sensitivity and low specificity. Therefore, we conclude that a larger study is warranted, with removing or adding predictors for model improvement.
AFRIKAANSE OPSOMMING: Wereldwyd is servikale kanker die vierde mees algemene kanker onder vroue. Aanhoudende infeksie met hoe-risiko menslike papillomavirus (HR-MPV) word getoon as die oorsaaklike faktor in servikale kanker ontwikkeling. Vroue wat met MIV leef is ses keer meer geneig tot servikale kanker ontwikkeling. Die doel van hierdie studie was om HR-MPV tipes te identifiseer in sitologiemonsters van MIV-positiewe en MIV-negatiewe vroue wat, met behulp van ā€˜n Papsmeer, met LSIL, HSIL, ASC-US, en ASC-H gediagnoseer is. Die gelyktydige uitdrukking van p16INK4a en Ki-67 in hierdie monsters was ook geevalueer tesame met die metileringstatus van CADM1, MAL en miR124-2 geen. Die studiedeelnemers was vroue tussen die ouderdom van 21 jaar tot 60 jaar wat na Kolposkopie-kliniek by Tygerberg Akademiese Hospitaal verwys is. Servikale intraepiteelselle is in Surepath-medium versamel. Die Hybrispot MPV direktevloeiskyfiestel is gebruik om HR-MPV tipes in hierdie monsters te op te spoor, terwyl die mede-uitdrukking van p16INK4a/Ki-67 proteiene met die CINtecR Plus sitologieimmunositochemie- stel geevalueer is. DNS is uit die oorblywende servikale selle geisoleer en die kwaliteit en kwantitieit van die DNS was met behulp van fluorometrie en spektrofotometrie bepaal. Geisoleerde DNS is bisulfiet omgeskakel en die metileringstoetse vir die CADM1, MAL en miR-124 geen is gedoen met behulp van die onderskeie EpiMelt-toetse. Die resultate van MPV DNA analise was geassosieer met sitologiese diagnose sowel as MIV status. Die proporsie van vroue wat positief getoets het vir MPV was 74 % (51/69; 95% CI: 62,1%-83%), waarvan 70.6% (36/51) van vroue met MIV en 29.4% (15/51) MIV negatiewe vroue was. Dubbele kleuring van p16INK4a/Ki-67 kon in 45.6% (25/51) van monsters opgetel word. Monsters met HSIL-sitologie het ā€˜n p16INK4a/Ki-67 mede-kleuring patroon van 66,6% (16/24) getoon, wat die hoogste was in vergelyking met die ander sitologiegroepe. Die proporsie van die LSIL-groep waaring positiewe p16INK4a/Ki-67 dubbele kleuring aangetref was, was 33,3% (4/12), terwyl die van die ACS-US- en ASC-H-groepe 25% (2/8) en 23% (3/13) was. CADM1 metilering is in 12.3% (7/57) van monsters opgespoor, terwyl MAL en die miR-124-2 gene metilering in onderskeidelik 14% (8/57) en 12.3% (7/57) van die monsters getoon het. HPV-infeksie is opgespoor in 28.1% (16/57) van die monsters met gemetileerde CADM1, MAL en miR-124-2 gene. Beduidende verwantskap is gevind tussen HR-MPV en miR-124-2 metilering. Die logistiese regressiemodel-analise wat voorspellers soos HR-MPV, p16INK4a en Ki-67 medeuitdrukking gebruik, sowel as die metileringstatus van die CADM1, MAL en miR-124-2-gene, vir LSIL-sitologie het lae sensitiwiteit en hoe spesifisiteit getoon , in teenstelling met die van die HSIL-model met hoe sensitiwiteit en lae spesifisiteit. Daarom kom ons tot die gevolgtrekking dat 'n groter studie geregverdig is, met die verwydering of byvoeging van voorspellers vir modelverbetering.
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Thesis (MSc)--Stellenbosch University, 2023.
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