Up-regulation of PINCH in the stroma of oral squamous cell carcinoma predicts nodal metastasis.

Particularly interesting new cysteine-histidine rich protein (PINCH), an adapter protein involved in integrin and growth factor signalling, is up-regulated in the stroma of colorectal, breast, prostate, lung and skin cancer. Strong stromal immunostaining for PINCH is an independent prognostic indicator for reduced survival in colorectal cancer, suggesting that PINCH is involved in the signalling that promotes tumour progression. Since no study on PINCH has been carried out in oral squamous cell carcinoma (OSCC), this study aimed to determine PINCH expression in OSCC and its clinicopathological significance. PINCH protein expression was examined by immunohistochemistry in 20 normal oral mucosa and in 57 OSCC specimens. The frequency of strong PINCH immunostaining was higher in tumour-associated stroma of OSCC (37%) as compared to normal oral mucosa (10%) (p=0.02). Strong PINCH stromal immunostaining predicted nodal metastasis: 19/26 (73%) OSCC cases with nodal metastasis had strong PINCH immunostaining compared to 9/31 (29%) cases without nodal metastasis (p=0.02). The PINCH expression in OSCC was more intense in stroma at the invasive edge than in intratumoural stroma. In conclusion, the up-regulation of PINCH protein in stroma may be involved in promoting invasion and metastasis in OSCC.