Oropharyngeal squamous cell carcinomas differentially express granzyme inhibitors

Abstract

Objectives: Patients with human papillomavirus (HPV)-positive oropharyngeal squamous cell carcinomas (OPSCCs) have an improved prognosis compared to HPV-negative OPSCCs. Several theories have been proposed to explain this relatively good prognosis. One hypothesis is a difference in immune response. In this study, we compared tumor-infiltrating CD3+, CD4+, CD8+ T-cells, and granzyme inhibitors (SERPINB1, SERPINB4, and SERPINB9) between HPV-positive and HPV-negative tumors and the relation with survival.

Methods: Protein expression of tumor-infiltrating lymphocytes (TILs) (CD3, CD4, and CD8) and granzyme inhibitors was analyzed in 262 OPSCCs by immunohistochemistry (IHC). Most patients (67%) received primary radiotherapy with or without chemotherapy. Cox regression analysis was carried out to compare overall survival (OS) of patients with low and high TIL infiltration and expression of granzyme inhibitors.

Results: HPV-positive OPSCCs were significantly more heavily infiltrated by TILs (p < 0.001) compared to HPV-negative OPSCCs. A high level of CD3+ TILs was correlated with a favorable outcome in the total cohort and in HPV-positive OPSCCs, while it reached no significance in HPV-negative OPSCCs. There was expression of all three granzyme inhibitors in OPSCCs. No differences in expression were found between HPV-positive and HPV-negative OPSCCs. Within the group of HPV-positive tumors, a high expression of SERPINB1 was associated with a significantly worse overall survival.

Conclusion: HPV-positive OPSCCs with a low count of CD3+ TILs or high expression of SERPINB1 have a worse OS, comparable with HPV-negative OPSCCs. This suggests that the immune system plays an important role in the carcinogenesis of the virally induced oropharynx tumors.

Keywords: Granzyme inhibitors; Human papillomavirus; Oropharynx squamous cell carcinoma; Tumor microenvironment; Tumor-infiltrating lymphocytes.

Fig. 1

a Staining patterns of CD3+, CD4+, and CD8+. Example of a 0.6 mm TMA core with low expression on the left side (A) and high expression on the right side for CD3+ (B) (magnification 10× and magnification 20×). The same for CD4+ (C, D) and CD8+ (E, F). b Staining patterns of granzyme B, SERPINB1, SERPINB4, and SERPINB9. Example of a 0.6 mm TMA core with low expression on the left side compared to high expression on the right side for granzyme B (A, B), SERPINB1 (C, D), SERPINB4 (E, F), and SERPINB9 (G, H) (magnification 10× and magnification 20×)

Fig. 1

a Staining patterns of CD3+, CD4+, and CD8+. Example of a 0.6 mm TMA core with low expression on the left side (A) and high expression on the right side for CD3+ (B) (magnification 10× and magnification 20×). The same for CD4+ (C, D) and CD8+ (E, F). b Staining patterns of granzyme B, SERPINB1, SERPINB4, and SERPINB9. Example of a 0.6 mm TMA core with low expression on the left side compared to high expression on the right side for granzyme B (A, B), SERPINB1 (C, D), SERPINB4 (E, F), and SERPINB9 (G, H) (magnification 10× and magnification 20×)

Fig. 2

Kaplan–Meier curves for OPSCC overall survival. Kaplan–Meier curves of OS. a For high levels (>150) of intratumoral CD3+ cells versus low levels in the total cohort of OPSCC. Log-rank p < 0.001, hazard ratio = 0.36 (0.21–0.61), p < 0.001. b For HPV-positive tumors. Log-rank p = 0.029, hazard ratio = 0.29 (0.09–0.95), p = 0.042 c For HPV-negative tumors. Log-rank p = 0.060, hazard ratio = 0.61 (0.37–1.03), p = 0.065. d Kaplan–Meier OS curve for SERPINB1 expression stratified for HPV status. It shows that the OS of HPV-positive tumors with a high SERPINB1 expression is comparable to HPV-negative patients