Changes in the pattern of aldehyde dehydrogenase activity in primary and metastatic adenocarcinomas of the human...

The activity of aldehyde dehydrogenase (ALDH) was measured in primary and metastatic human colonic adenocarcinomas. The enzyme was determined with either propionaldehyde and NAD (P-NAD) or with benzaldehyde and NADP(B-NADP). Primary colonic adenocarcinomas had levels of P-NAD activity similar to those of the adjacent normal mucosa, but relatively higher B-NADP activity. Also the metastatic colonic adenocarcinomas of the liver had lower P-NAD and higher B-NADP activity than the normal hepatic parenchyma. The level of ALDH was in general lower in the normal colonic mucosa, when compared to the liver. Histochemical staining of cryostat tissue sections revealed that the enzyme is exclusively confined to the epithelial cells of the glandular ducts of the colonic mucosa. This may explain, along with the significant anaplastic changes of the mucosa, the variation of ALDH activity detected in the homogenates of the primary and metastatic adenocarcinomas. However, the ratio of B-NADP activity in the adenocarcinomas versus the adjacent normal tissues was constantly and significantly high.