The Distinctive Features behind the Aggressiveness of Oral and Cutaneous Squamous Cell Carcinomas

Abstract

Squamous cell carcinomas arise from stratified squamous epithelia. Here, a comparative analysis based on recent studies defining the genetic alterations and composition of the stroma of oral and cutaneous squamous cell carcinomas (OSCC and CSCC, respectively) was performed. Both carcinomas share some but not all histological and genetic features. This review was focused on how mutations in tumor suppressor genes and protooncogenes cooperate to determine the differentiation, aggressiveness, and metastatic potential of OSCC and CSCC. In fact, driver mutations in tumor suppressor genes are more frequently observed in OSCC than CSCC. These include mutations in TP53 (encoding pP53 protein), CDKN2A (encoding cyclin dependent kinase inhibitor 2A), FAT1 (encoding FAT atypical cadherin 1), and KMT2D (encoding lysine methyltransferase 2D), with the exception of NOTCH (encoding Notch receptor 1), whose mutation frequency is lower in OSCC compared to CSCC. Finally, we describe the differential composition of the tumor microenvironment and how this influences the aggressiveness of each tumor type. Although both OSCC and CSCC tumors are highly infiltrated by immune cells, high levels of tumor-infiltrating lymphocytes (TILs) have been more frequently reported as predictors of better outcomes in OSCC than CSCC. In conclusion, OSCC and CSCC partially share genetic alterations and possess different causal factors triggering their development. The tumor microenvironment plays a key role determining the outcome of the disease.

Matrix‐based molecular mechanisms, targeting and diagnostics in oral squamous cell carcinoma

“…The ECM plays an integral role in tumor invasion and metastatic development, particularly in OSCC 12 . Signals from host cells that typically reduce MMP proteolytic activity and matrix turnover and thereby provide protection against tumor growth, allow OSCC cells to utilize the ECM to their advantage and lead to OSCC progression 72 . While TIMPs regulate proenzyme activation that results in an invasive phenotype, 73 OSCC cells synthesize and secrete MMPs, which play a significant role in the release of bioactive fragments of ECM proteins.…”