Breath methane and colorectal cancer.

The association between colorectal cancer and breath methane is controversial. We compared a group of 59 patients with unresected colorectal cancer with a group of control subjects matched for age and sex. We also studied 43 of the cancer patients before and 3-6 months after resection. Sixty-three per cent of the patients with unresected carcinoma and 56% of the control subjects were methane excretors (NS). We found no significant change in methane excretion status after resection. Because recent colonic cleansing has been shown to influence methane production in the colon, 15 breath methane excretors were studied immediately before the start of cleansing, on the day of colonoscopy, and on the 7th day thereafter. Forty per cent became breath-methane-negative on the day of colonoscopy, but all 15 were excretors with a median of 60% of the precleansing concentration on the 7th day. The present study does not confirm an association between breath methane and colorectal cancer. It is unlikely that colonic cleansing procedures influenced the results of this study.

[The role of proteases in the growth, invasion and spread of cancer cells]. / Proteasers betydning for cancercellers vekst, invasivitet og spredning.

Cancer cells show a greater capability than normal cells do to break down proteins in the surrounding tissue. This tissue destruction involving proteolytic enzymes is probably essential for the invasion and metastatic spread of malignant cells. The process takes place through an interplay of proteolytic enzyme systems where plasmin-mediated proteolysis plays an important role. Plasminogen activator activity and receptors for plasminogen activators have been discovered in tumors, mainly in areas with invasive growth and tissue degradation. Patients with malignant diseases often demonstrate abnormalities in their blood coagulation, including hyperaggregability of platelets. Experimental research has shown that therapy with antiplatelet drugs, and prophylaxis with protease inhibitors, can limit spread of tumors.