Tissue mechanics and expression of TROP2 in oral squamous cell carcinoma with varying differentiation

Abstract Background Trophoblast cell surface antigen 2 (TROP2) is overexpressed in many squamous cell carcinomas and promotes tumor development and invasion. The association between TROP2 expression and occurrence and development of oral squamous cell carcinoma (OSCC) remains to be understood.Methods We investigated the role of TROP2 in OSCC patients using a combination of biophysical approaches. A total of 108 OSCC patient specimens with varying degrees of differentiation were subjected to hematoxylin and eosin staining, immunohistochemistry, Kaplan-Meier survival curve analysis, and atomic force microscopy to analyze TROP2 expression, morphology, and mechanical properties of OSCC tissues.Results TROP2 was overexpressed in 34% of poorly differentiated OSCC samples. High levels of TROP2 were associated with 10.2% survival rate lower than 45.4% and patient age (odds ratio [OR]=0.437, P=0.039, 95% confidence interval [CI, 0.198–0.966]), tumor size (OR=13.148, P=0.000, 95% CI [5.060–34.168]), and TNM stage (OR=0.141, P=0.000, 95% CI [0.082–0.244]). Average surface roughness of low, medium, and highly differentiated OSCC tissues were 448.9±54.8, 792.7±83.6, and 993.0±104.3 nm, respectively. The Pearson coefficient revealed a negative association between tumor stiffness and TROP2 expression (r=-0.84, P<0.01).Conclusion Overexpression of TROP2 negatively associated with patient survival, degree of tumor differentiation, and tissue mechanics. Taken together, our findings demonstrated that TROP2 may be an indicator of OSCC differentiation leading to the altered mechanical properties of OSCC tissues.