There is growing evidence which indicates that the development and the biological features of cancer such as the invasion, metastases and recurrence are related to the presence and behavior of the cancer stem cells (CSC). However, the regulatory mechanisms underlying CSCs-specific properties are poorly determined, the Hippo pathway has emerged as a fundamental regulator underlying CSCs stemness.

Immunohistochemical method was used to examine the immunoexpression of SOX2, TAZ and α-SMA in oral squamous cells carcinomas: with metastases –

OSCC M+ (n = 42), and without metastases – OSCC M– (n = 44), and 17 control cases.

The immunoexpression of SOX2, TAZ and α-SMA was significantly increased in both group of OSCC in comparison to control groups. Moreover, significantly increased TAZ and α-SMA immunoexpression were found in OSCC M+ compared to OSCC M-. In OSCC M+ and OSCC M- groups there were statistically significant correlations between the immunoexpression of TAZ vs SOX2 (r = 0.56, p < 0.001; r = 0.33, p < 0.03 respectively), and TAZ vs α-SMA (r = 0.64, p < 0.001; r = 0.67, p < 0.001 respectively). Moreover, there was statistically significant association between TAZ^high/SOX2^high coexistent immunoexpression and the presence of metastases (p < 0.007).

Our results may suggest that SOX2 and TAZ could potentially cooperate and contribute to process of metastasis, especially in cases with TAZ^high/SOX2^high expression.