Expression of pituitary-tumour transforming gene in colorectal tumours

Background Basic fibroblast growth factor promotes angiogenesis and mitogenesis in colon carcinomas. Pituitary tumour transforming gene (PTTG(1)) causes in-vitro and in-vivo transformation, regulates secretion of basic fibroblast growth factor. and inhibits chromatid separation. Most normal tissues show little or no PTTG(1) expression but cancer cells express the gene abundantly. We postulated that PTTG(2) expression in colorectal tumours is related to tumour invasiveness. Methods PTTG(1) gene and protein expression were assessed in 68 colorectal tumours and compared with invasive characteristics, such as lymph-node invasion. evidence of metastases, tumour Vessel density, and expression of basic fibroblast growth factor. PTTG(1) expression is given in terms of the fold-increase over that in normal-adjacent colorectal tissue. Findings PTTG(1) was overexpressed in all of 48 colon carcinomas (median fold-increase 2.2 [IQR 1.8-3.3]) and in 19 of 20 colonic polyps (2.2 [1.6-3.1]) compared with normal colonic tissue. Invasion of surrounding lymph nodes was associated with higher PTTG(1) expression than in carcinomas limited to the bowel wall (3.4 [2.1-5.9] vs 1.9 [1.7-2.4], p=0.007), and higher PTTG(1) expression was seen in more vascular than in less vascular tumours (2.6 [1.9-5.1] vs 1.9 [1.8-2.5], p=0.04). Interpretation Increased tumour PTTG(1) expression may be a marker of invasive colorectal carcinoma and could represent a new therapeutic target.