Prognostic significance of cell cycle-associated proteins p16, pRB, cyclin D1 and p53 in resected oropharyngeal carcinoma

Abstract

BackgroundHuman papillomavirus (HPV)-related oropharyngeal squamous cell carcinoma (OPSCC) has an improved outcome and may allow for treatment de-escalation. High-risk HPV (HR-HPV) infection is associated with deregulated expression of the cell cycle-associated proteins p16INK4, pRB, cyclin D1 and p53. The objective of this study was to assess cell cycle proteins as potential surrogate markers for HR-HPV DNA testing to identify OPSCC with favorable prognosis after resection.MethodsTissue microarray cores of 313 surgically treated OPSCC were stained for p16INK4a, pRB, cyclin D1 and p53 using immunohistochemistry. Protein expression was scored as high or low based on the proportion of positive carcinoma cells. Tumor samples were analysed for HR-HPV DNA with polymerase chain reaction-based testing. Associations between cell cycle protein expression and HR-HPV DNA status were evaluated by calculating sensitivity, specificity, predictive values, and diagnostic odds ratios (DOR). Kaplan-Meier and Cox regression analysis were applied to evaluate associations between cell cycle protein expression and patient outcome.ResultsHigh expression of p16INK4a, cyclin D1, pRB and p53 in tumor cells were observed in 51.8%, 51.4%, 41.9% and 33.5% of OPSCC, respectively. HR-HPV DNA positive were 158/313 (50.5%) tumor samples (HPV16: 147, HPV18: 1, HPV33: 5, HPV35: 2, HPV56: 2, and HPV59: 1). P16INK4a showed a higher DOR to predict HR-HPV DNA positivity than pRB, cyclin D1 and p53. Both the p16INK4a/pRB and the p16INK4a/pRB/cyclin D1/p53 signatures had lower DOR than p16INK4a alone. Improved 5-year overall and disease-specific survival were associated with HR-HPV DNA positivity, high p16INK4a, low pRB, low cyclin D1, and low p53 expression. Associations with improved outcome were also observed for the marker combinations high p16INK4a/positive HR-HPV DNA, high p16INK4a/low pRB and high p16INK4a/low pRB/low cyclin D1/low p53. In a multivariate analysis adjusted for age, smoking history, pT and pN category, high p16INK4a expression showed the lowest hazard ratio for death.ConclusionsHigh p16INK4a expression is a reliable marker for survival prognostication in surgically treated OPSCC patients. Protein signatures including the pRB, cyclin D1 and p53 proteins do not further increase the prognostic performance of p16INK4a as a single marker.

Analysis of HPV-Positive and HPV-Negative Head and Neck Squamous Cell Carcinomas and Paired Normal Mucosae Reveals Cyclin D1 Deregulation and Compensatory Effect of Cyclin D2

“…Given that cyclin D1 is required for tumor formation induced by HPV proteins E6 and E7 [52], it indicated that cyclin D1 downregulation may also contribute to a better prognosis of HPV(+) patients. Indeed, previous studies have associated low cyclin D1 expression in HPV(+) tumors with improved survival rates when in combination with high p16 INK4a , low pRb and low p53 [53,54]. However, we have not observed an improved outcome in HPV(+) patients who exhibit low expressions of cyclin D1 mRNA.…”

HPV Detection in Head and Neck Squamous Cell Carcinomas: What Is the Issue?

“…Sensitivity of p16 immunostaining in the oropharynx is around 80–90% ( 8 , 62 , 63 , 70 , 71 , 81 , 82 , 87 , 88 , 92 – 95 ). One study compared the performances of p16 immunostaining according to the threshold of positivity used to assess p16 immunostaining positivity ( 96 ).…”

“…Further studies led in different OPSCC populations and comparing different thresholds of positivity are required. Considering that specificity of p16 immunostaining varies from 80 to 90% ( 8 , 62 , 63 , 70 , 71 , 81 , 82 , 87 , 88 , 92 – 95 ), some patients with OPSCC may be diagnosed as having a transcriptionally active HPV infection when it is not the case. Rietbergen et al showed especially that OPSCCs with a p16 immunostaining, and no transcripts of E6 and E7 proteins have a poorer prognosis compared to those with E6 and E7 transcripts ( 86 ).…”

mTOR Signalling in Head and Neck Cancer: Heads Up

“…Some of the mutated genes frequently associated with HNSCC are TP53 , CDKN2A , FAT1 , NOTCH1 , EGFR, HRAS , and PI3KCA [23,24,25,26,27], and the mutations in these genes are recognised as drivers of tumour development and progression. In HPV + subtype patients, high-risk HPV infection has been associated with the abnormal expression of proteins associated with cell cycle regulation, including p53 and p16 (CDKN2A) [21,28,29]. Functional TP53 inhibits the mammalian target of rapamycin (mTOR) pathway through AMPK in response to cellular stresses and DNA damage [21].…”