Medizinische Universität Graz - Research portal
Selected Publication:
Gallob,M.
PD-L1 and p16 expression in oropharyngeal squamous cell carcinomas
Humanmedizin; [ Diplomarbeit ] Graz Medical University; 2019. pp. 57
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- Authors Med Uni Graz:
- Advisor:
- Brcic Luka
- Wolf Axel
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- Abstract:
- Introduction: Squamous cell carcinoma is the most common malignant tumour in the oropharyngeal region. The overall survival is poor, with a 5-year survival rate of approximately 60%. Immunotherapy is demonstrating promising results for those tumours. Data about PD-L1 expression in this carcinoma and its relation with prognosis, is limited and controversial. HPV status is the most important prognostic factor in oropharyngeal squamous cell carcinoma (OPSCC). The aim of this study was to assess the overall expression of PD-L1 and p16 in OPSCC, and to correlate it in different matched tumour samples and with survival data. Methods: Patients with OPSCC diagnosed from 2000 until 2016 with adequate clinical data were selected. Immunohistochemical analysis was performed with PD-L1 and p16 antibodies. Positive reaction was expressed as a percentage of all tumor cells, using two different groupings for PD-L1. P16 was regarded positive, when nuclear and cytoplasmic staining was present in ≥70% of tumour cells. Positivity of primary tumors was correlated with paired metastasis as well as with survival and expression of the respective other biomarker. Results: Altogether 93 patients with 230 tissue samples were analysed. There was no statistically significant difference between the PD-L1 staining in primary tumor and metastasis, nor a correlation between PD-L1 positivity and survival. There was no statistically significant difference in p16 positivity between different tumor sample locations. P16 positivity in resection samples and lymph node metastases correlated significantly to longer overall survival (p = 0.039, and p = 0.002, respectively). In primary biopsies, there was a statistically significant correlation between p16 and PD-L1 expression, in ungrouped analysis (p= 0.034) and grouping A (p= 0.036). Conclusion: Our study showed, for the first-time, prevalence of HPV associated OPSCC in Austria, and correlated this throughout different matched sample types, as well as with survival. The same was done with the expression of PD-L1, today still the most important predictive biomarker for many immune-checkpoint inhibitors. Complexity and pitfalls of PD-L1 evaluation was demonstrated, depending on the cut-offs and location of the samples. Furthermore, we have demonstrated concordance in the evaluation of HPV positivity, using p16 immunohistochemistry, as well as PD-L1 expression, between different tumour samples, providing useful information for optimal therapy planning.