Plasma gelatinase activity does not reflect disease activity after operation for colorectal cancer

To investigate if plasma matrix metalloproteinase (MMP)-2 or -9 are better markers for disease activity than carcinoembryonic antigen (CEA) in the postoperative follow-up of colorectal cancer patients.

A prospective study was performed including 61 patients operated for primary colorectal cancer. The follow-up was for at least 2 years and postoperative blood samples were obtained periodically with 3-month intervals. Plasma gelatinase activity was measured with quantitative gelatin zymography and serum CEA with a specific immunoassay.

Zymographic analysis of plasma samples revealed the presence of the proforms, but not the active forms, of both MMP-2 and -9. Prior to the detection of recurrent disease or metastasis in potentially curatively operated colorectal cancer patients, the changes in proMMP-2, -9 and CEA blood levels were determined. ProMMP-2 and -9 plasma levels changed little in this period and changes between patients with and without disease relapse were not statistically significant. In contrast, patients with disease relapse showed a significant increase (p = 0.002) in CEA in the two consecutive serum samples prior to the detection of recurrent disease or metastasis. Similarly, prior to death due to colorectal cancer, proMMP-2 and -9 plasma levels showed no significant change, whereas CEA levels increased considerably and significantly (p < 0.001) when compared to changes found in survivors.

Plasma proMMP-2 and -9 activities show no potential value as prognostic markers in the follow-up of colorectal cancer.