High frequency of concomitant nm23-H1 and E-cadherin transcriptional inactivation in primary non-inheriting colorectal carcinomas

This study evaluated the added significance of nm23-H1 to that of E-cadherin in determining metastatic proclivity in primary sporadic colorectal carcinomas (SCRCs). A clinical cohort of 52 SCRCs was examined for the significance of nm23-H1 and E-cadherin mRNA levels and E-cadherin protein expression levels into the progression of colorectal tumor invasion, determined by their relevance compared with conventional biological markers. A more than twofold decreased expression of nm23-H1 mRNA was reported in 28/52 (54%) of the carcinomas and was positively associated with the presence of nodal metastases and Astler-Coller stages B1 and B2 in 29% and 35% of the SCRCs, respectively. Reduced expression of E-cadherin mRNA was reported in 38.5% of the carcinomas and was similarly associated with stages Astler-Coller B1 and B2 in 27% of the SCRCs. Decreased E-cadherin immunohistochemical expression (grades II and III) was observed in 67% of the samples. E-cadherin mRNA and protein expression were significantly related to each other. The nm23-H1 (+)/E-cadherin (+) coexpression profile was observed in 31% and was significantly related to the absence of lymph node metastases in 31% and stages Astler-Coller B1 and B2 in 29% of the carcinomas examined. Furthermore, the nm23-H1 (-)/E-cadherin (+) coexpression profile was coupled to decreased E-cadherin immunohistochemical protein detection (grade II) in 21 % of the cases examined. These findings suggest that impairment of nm23-H1 expression is an early event into the progression of colorectal metastasis that precedes E-cadherin transcriptional silencing in the majority of SCRCs examined. Nm23-H1 may therefore play an important role in suppressing the early steps of metastasis in sporadic cases of colorectal carcinomas.