MMP-9 and cathepsin B expression in tumor budding as an indicator of a more aggressive phenotype of colorectal cancer (CRC).

BACKGROUND

The aim of this study was to clarify the relationship between the expression of MMP-9 and Cathepsin B (CathB) at the main tumor mass and lymph node metastases and the presence of tumor budding and vascular invasion at the invasion front, as well as lymph node involvement.

PATIENTS AND METHODS

The immunohistochemical expressions of MMP-9 and CathB were studied in 55 specimens of colorectal adenocarcinomas (pT3, G2). A standard avidin-biotin immunoperoxidase staining method (ABCu-NCL) was performed on 4-microm paraffin-embedded tissue sections with a mouse anti-human MMP-9 and CathB monoclonal antibody.

RESULTS

Positive immunostaining for MMP-9 in the primary tumor was observed in 30/55 (54.6%) cases and in 29 cases (52.7%) for CathB. A statistically significant association was found between the expressions of MMP-9 and CathB in the primary tumor and lymph node involvement (p<0.01). The expression of CathB in the primary tumor was associated with the presence of tumor budding and vascular invasion (p<0.01); but no such association was found for MMP-9. The expressions of MMP-9 and CathB in buds were strongly associated with lymph node involvement (p<0.01). However, the presence of vascular invasion was significantly associated only with positive expression of CathB in the buds (p<0.01).

CONCLUSION

If the presence of budding in the colorectal cancer invasive front indicates higher invasive potential, the present results seem to suggest the existence of a strong relationship between MMP-9 and CathB expressions in the buds and a more aggressive tumor phenotype.