Discrepancy of p16 immunohistochemical expression and HPV RNA in penile cancer. A multiplex in situ hybridization/immunohistochemistry approach study

Abstract

Background The high-risk human papillomavirus (HPV) infection represents one of the main etiologic pathways of penile carcinogenesis in approximately 30–50 % of cases. Several techniques for the detection of HPV are currently available including Polymerase chain reaction-based techniques, DNA and RNA in situ hybridization (ISH), p16 immunohistochemistry (IHC). The multiplex HPV RNA ISH/p16 IHC is a novel technique for the simultaneous detection of HPV E6/E7 transcripts and p16INK4a overexpression on the same slide in a single assay. The main aim of this study was to evaluate the discrepancy of p16 IHC expression relatively to HPV RNA ISH in penile cancer tissue. Methods We collected a series of 60 PCs. HPV has been analysed through the RNA ISH, p16 IHC and the multiplex HPV RNA ISH/p16 IHC. Results The multiplex HPV RNA ISH /p16 IHC results in the series were in complete agreement with the previous results obtained through the classic p16 IHC and HPV RNA scope carried out on two different slides. The multiplex HPV RNA ISH /p16 IHC showed that HPV positivity in our series is more frequently in usual squamous cell carcinoma than in special histotypes (19 out of 60 − 15 %- versus 6 out of 60 − 10 %-), in high-grade than in moderate/low grade carcinomas (6 out of 60 − 10 %- versus 4 out of 60 − 6.7 %-). In addition, our data revealed that in 5 out of 20 cases with p16 high intensity expression is not associated with HPV RNA ISH positivity. Conclusions Our findings emphasize that the use of p16 as a surrogate of HPV positivity was unsuccessful in approximatively 8 % of cases analysed in our series. Indeed, p16 IHC showed a sensitivity of 100 % and a specificity of 71 %, with a positive predictive value (PPV) of 54 % and a negative predictive value of 100 %; when considering high intensity, p16 IHC showed a sensitivity of 100 %, a specificity of 89 %, with a PPV of 75 % and NPV of 100 %. Since HPV positivity could represent a relevant prognostic and predictive value, the correct characterization offered by this approach appears to be of paramount importance.

Mutational Signature and Integrative Genomic Analysis of Human Papillomavirus-Associated Penile Squamous Cell Carcinomas from Latin American Patients

“…Hence, considering the high frequency of CDKN2A nonsense variants in highrisk HPV advanced PSCC, we reinforce that p16 immunoexpression may be ineffective as an HPV marker in a significant subset of PeCa. Our results corroborate those of Zito Marino et al [51], who highlighted the importance of using at least two methods to avoid the misclassification of HPV penile tumors in clinical practice.…”

Identification of differentially expressed genes and pathways for risk stratification in HPV-associated cancers governing different anatomical sites

“…However, overexpression of p16 is infrequently observed in some HPVnegative patients [42]. To overcome this limitation, a multimodal approach combined with p16 IHC is being considered, which reduces false-positive and false-negative cases in HPV detection [43,44]. We divided the high-risk group and the low-risk group in HPV-positive cancers using the HPPI risk scoring system we previously developed, which is different from the existing methods to detect high-risk HPV.…”

Immunotherapy in Penile Squamous Cell Carcinoma: Present or Future? Multi-Target Analysis of Programmed Cell Death Ligand 1 Expression and Microsatellite Instability

“…Ubiquitin C and dapB were used as positive and negative controls, respectively. A positive HPV ISH test result was defined as positive if any of the malignant cells showed brown punctate dot-like nuclear and/or cytoplasmic positivity ( 19 ).…”