It is unclear how expression of the FHIT (fragile
histidine triad) gene by the
colorectal neoplasm correlates with histogenesis and progression of the disease. We studied the association between expression of
Fhit protein and development of
colorectal carcinoma (CRC). We also examined relations between
Fhit protein expression, macroscopic type, Ki-67 labeling index (LI), and p53 overexpression in
carcinoma in situ. We examined 27 colorectal
adenomas, 82
carcinomas in situ and 21 invasive
CRCs resected endoscopically or surgically. The
carcinomas in situ comprised three macroscopic types: polypoid (n=27), superficial (flat elevated, n=27; depressed, n=10) and granulonodular laterally spreading
tumor (G-LST, n=23). Fhit, Ki-67, and p53 overexpression were examined immunohistochemically. Levels of
Fhit protein were lower in invasive CRC than in
adenoma and
carcinoma in situ (p<0.01). In
carcinoma in situ, reduced Fhit expression was observed in 7 of 22 (31.8%) polypoid types, 13 of 27 (48.1%) superficial flat elevated types, 8 of 10 (80%) superficial depressed types and 7 of 23 (30.4%) G-LST. Frequencies of reduced Fhit expression were significantly higher in the polypoid type and G-LST lesions than in the depressed type (p<0.05). Reduced expression of
Fhit protein was related significantly to Ki-67 LI and p53 overexpression in
carcinoma in situ (p<0.01). The present findings suggest that reduced expression of
Fhit protein is related to development of
colorectal neoplasm. Polypoid CRC and G-LST appear to differ from superficial depressed CRC in terms of Fhit expression.