Colorectal carcinogenesis is associated with serious oxidative stress and confirms that gradual advancement of oxidative-antioxidative disorders is followed by progression of colorectal cancer.

Mutations that inactivate the transactivational ability of TP53 are more frequent in advanced CRC and are associated with worse prognosis in this stage of disease.

The principal enzymes catalyzing the conversion of ethanol to acetate are alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH). The activities of these enzymes are elevated in the serum during the course of alcoholism or cirrhosis. In previous investigations we have found elevated levels of ADH, ALDH, and class I ADH activity in liver cancer cells. It can suggest that these changes may be reflected by enzyme activity in the serum. In this work, the activity of ADH isoenzymes, and ALDH in the sera of patients with liver cancer was measured. Serum samples were taken from 64 patients (28 drinkers, 36 nondrinkers), with liver cancer. 25 patients had primary and 39 metastatic liver tumors. Total ADH activity was measured by photometric method with p-nitrosodimethylaniline (NDMA) as a substrate and ALDH activity by the fluorimetric method with 6-methoxy-2-naphtaldehyde as a substrate. For the measurement of the activity of class I and II isoenzymes we employed the fluorimetric methods, with class-specific fluorogenic substrates. The activity of class III ADH was measured by the photometric method with formaldehyde and class IV with m-nitrobenzaldehyde as a substrate. A statistically significant increase of class I ADH isoenzymes was found in the sera of cancer patients. The median activity of this class isoenzyme in the total cancer group increased about 51% (2.94 mU/L) in the comparison to the control level (1.43 mU/L). The activity of the class I ADH isoenzyme was significantly higher in the sera of patients with metastatic tumors than with primary cancers. The activity of this class in the sera of drinkers and group of moderate drinkers was significantly higher in comparison to the control group and higher in the sera of heavy drinkers when compared with moderate drinking patients. The total ADH activity was significantly higher (44%) among patients with cancer than healthy ones. The activity of class I ADH isoenzymes was elevated only in the serum of patients with metastatic liver cancer. This increase of activity seems to be caused by the enzyme released from liver cancer cells and primary tumors originating in other organs.

Differences in the activities of total ADH, ALDH and class I ADH isoenzyme between cancer liver tissues and healthy hepatocytes might be a factor in ethanol metabolism disorders, which can intensify carcinogenesis.

Various isoenzymes of alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) exist in human colorectal mucosa. In our last experiments we have shown that ADH and ALDH are present also in colorectal cancer cells. Moreover the activities of total ADH and class I isoenzymes were significantly higher in cancer tissue than healthy mucosa. This may suggest that these changes may be reflected by enzyme activity in the serum. Therefore, we have measured the activity of total ADH, and classes I-IV of this enzyme and ALDH in the sera of patients suffering from this cancer. Total ADH activity was measured by a photometric method with p-nitrosodimethylaniline (NDMA) as a substrate and ALDH activity by the fluorometric method with 6-methoxy-2-naphtaldehyde as a substrate. For the measurement of the activity of class I and II isoenzymes we employed fluorometric methods, with class-specific fluorogenic substrates. The activity of class III ADH was measured by the photometric method with formaldehyde and class IV with m-nitrobenzaldehyde as a substrate. Serum samples were taken for routine biochemical investigations from 52 patients with colorectal carcinoma before treatment. A statistically significant increase of class I ADH isoenzymes was found. Therefore the total ADH activity was also significantly increased. The total ALDH and the activity of other tested ADH isoenzymes were unchanged. We also observed the increasing tendency of ADH I activity in accordance with the advance of disease. The activity of class I ADH isoenzymes was elevated in the serum of patients with colorectal cancer. This activity was derived from colorectal cancer cells and probably from severely damaged liver by metastatic disease.