[RhoA gene expression in colorectal carcinoma]

To investigate the expression of RhoA mRNA in colorectal neoplasms.

Total RNA was extracted from 42 surgically resected specimens of colorectal caricinoma and normal mucosa close to the lesions. Afier the optimal reverse transcription polymerase chain reaction (RT-PCR) condition was found, the mRNA expression levels of the RhoA gene in the lesions and the normal mucosa were examined semi-quantitatively and the relation between these expression levels and clinical pathological markers was compared.

The expression of RhoA gene mRNA in lesion of colorectal carcinoma was significantly higher than that in contiguous normal mucosa (1.8 +/- 0.6 vs 0.9 +/- 0.4, P < 0.01). The ratio of RhoA expression in neoplasm to that in contiguous mucosa was 2.02 +/- 0.82. Based on this ratio the 42 patients were divided into two groups: overexpression group (19 cases) and high-expression group (23 cases). In the overexpression group the lesions of 14 cases were in Dukes C and Dukes D stages, and lymph node metastasis was found in 13 cases. In the high-expression group, only 9 out of the 23 cases were in advanced stage and 8 cases showed lymph-node metastasis. Chi-squared test analysis demonstrated a significant difference in both aspects between these two groups (P < 0.05). The difference in number of metastatic lymph nodes between the two groups was statistically significant (P < 0.01). Mutation was not found in the RhoA gene sequence examined.

RhoA gene may play an important role in colorectal carcinogenesis and correlate with invasion and metastasis of colorectal carcinoma.