Stromal staining for PINCH is an independent prognostic indicator in colorectal cancer

Particularly interesting new cysteine-histidine-rich protein (PINCH), a LIM domain adapter protein that functions in the integrin and growth factor signal transduction pathway, is upregulated in stroma associated with many common cancers. The finding suggested that PINCH may be involved in promoting tumor-stromal interactions that support tumor progression, and, if so, tumors with abundant PINCH stromal staining may have a worse prognosis. To test this hypothesis, 174 primary colorectal adenocarcinomas with 39 distant normal mucosa samples and 26 metastases in the lymph nodes were studied by immunohistochemistry, and 7 additional colon tumors were studied by Western blot analysis and immunofluorescence. The abundance of PINCH protein in stroma increased from normal mucosa to primary tumor to metastasis (P <.05), and was more intense at the invasive margin than it was in the intratumoral stroma. Strong stromal immunostaining for PINCH was shown to predict a worse outcome (rate ratio 2.1, 95% CI 1.16-3.37, P=.01), independent of Dukes stage, growth pattern, and tumor differentiation. PINCH was detected in fibroblasts, myofibroblasts, and a proportion of endothelial cells of the tumor vasculature, supporting the involvement of PINCH in promoting tumor-stromal interactions that support tumor progression. Interestingly, stromal staining for PINCH was an independent prognostic indicator in colorectal cancer.