Active human papillomavirus involvement in Barrett's dysplasia and oesophageal adenocarcinoma is characterized by wild-type p53 and aberrations of the retinoblastoma protein pathway

Abstract

We have previously demonstrated that transcriptionally active high-risk HPV (hr-HPV) is strongly incriminated in Barrett's dysplasia (BD) and oesophageal adenocarcinoma (OAC) using mainly fresh frozen tissue. This study aimed to identify biomarkers of active HPV infection in Barrett's metaplasia, (BM)/BD/OAC by immunohistochemical staining (IHC) of formalin-fixed paraffin embedded (FFPE) tissue for aberrations of p53 and the retinoblastoma (pRb) pathway which are targets for the viral oncoproteins, E6/E7 respectively.

Prospectively, BM(n=81)/BD(n=72)/OAC(n=65) FFPE specimens were subjected to IHC staining for pRb, p16^INK4A, cyclin D₁, p53 and RNA in-situ hybridization (ISH) for E6/E7 transcripts. HPV DNA was determined via PCR in fresh frozen specimens. Viral load measurement (real-time PCR) and Next Generation Sequencing of TP53 was also performed.

Of 218 patients, 56 were HPV DNA positive [HPV16 (n=42), 18 (n=13), 6 (n=1)]. Viral load was low. Transcriptionally active HPV (DNA⁺/RNA⁺) was only found in the dysplastic and adenocarcinoma group (n=21). The majority of HPV DNA⁺/RNA⁺ BD/OAC were characterized by p16^INK4A_high (14/21, 66.7%), pRb_low (15/21, 71.4%) and p53_low (20/21, 95%) and was significantly different to controls [combination of HPV DNA^-/RNA^- (n=94) and HPV DNA⁺/RNA^- cohorts (n=22)]. p53_low had the strongest association with DNA⁺/RNA⁺ oesophageal lesions (OR=23.5, 95% CI=2.94-187.8, p=0.0029). Seventeen HPV DNA⁺/RNA⁺ BD/OAC identified as p53_low, were sequenced and all but one exhibited wild-type status. pRb_low/p53_low provided the best balance of strength of association (OR=8.0, 95% CI=2.6-25.0, p=0.0003) and sensitivity (71.4%)/specificity (71.6%) for DNA⁺/RNA⁺ BD/OAC.

Active HPV involvement in BD/OAC is characterized by wild-type p53 and aberrations of the retinoblastoma protein pathway. This article is protected by copyright. All rights reserved.

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