Abstract 901P
Background
Human papillomavirus-16 (HPV-16) infection in Head and Neck Squamous Cell Carcinoma (HNSCC) has a different prevalence through worldwide regions, it influences prognosis and treatment response and p16 staining is its surrogate biomarker. The density and composition of tumor-infiltrating lymphocytes (TIL) reflect biology and prognosis in different malignancies. We characterize TIL in Peruvian patients with HNSCC. We evaluate the influence of clinicopathological features including p16 & ki67 staining in tumor cells over TIL level.
Methods
CD3, CD8, p16, and Ki67 immunohistochemistry were performed on tissue microarrays (TMA), density of CD3/CD8 positive cells were analyzed with Visiopharm Tissuealign Software, and p16 status and ki67 level were evaluated by a pathologist. TIL was evaluated following the International TIL working group. Statistical analysis was performed with SPSS software.
Results
We included 178 HNSCC who came to the institute from 2005 to 2015 and who have enough archived tumor tissue to prepare TMAs. The median age was 65 y, most were female (56.7%) and the most frequent primary location was oral cavity (78.7%). The most frequent clinical stage was (CS) II (37.6%), the most histological grade was G2 (68.5%). Positive tumors for p16 were found in 10.1% (including 4 from the 9 oropharynx cases) and median Ki67 was 30%. Median follow-up was 16.3 months and 81 cases died. Staining of p16 was associated with oropharynx primary (44.4% vs 8.3%, p<0.001) and more frequent higher Ki67 tumor (88.9% vs 53%, p=0.004), but not to TIL (p=0.44), CD3 density (p=0.6), CD8 density (p=0.3) nor CD8/CD3 (p=0.13). Higher TIL was associated with higher Ki67 tumor (71.2% vs 48.8%, p=0.026), as well as with CD8 and CD3 density (Cohen's Kappa score= 0.698, p<0.001). Survival analysis found that CS III-IV were associated with shorter survival at 5-y (57.6 vs 63.4%, p=0.038). Higher TIL tends to be associated with longer survival (60 vs 51.2%, p=0.18). Neither p16 staining (p=0.679), ki67 (p=0.304) nor CD8/CD3 ratio (p=0.83) were associated with survival.
Conclusions
The presence of PVH surrogate marker, p16 is not frequent among Peruvian HNSCC, but associated with oropharynx location. Higher Ki67 was associated with both p16 and high TIL levels.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
FONDECYT 096-2017.
Disclosure
All authors have declared no conflicts of interest.