Promising anticancer compounds of the type 1,6-disubstituted 4,5,6,7-tetrahydropyrazolo[3,4-c]pyridin-7-ones were identified. The target compounds were readily synthesized in a large scale via a sequence of reactions starting from the commercially available primary amines. Their in vitro anti-proliferative activity has been evaluated on prostate (DU-145), colon (HT-29 and HCT-116) and melanoma (A375P) human cancer cell lines. The relationships between the structure and the anticancer activity, covering all tested cancer cell lines, revealed that the compound 5c with 2,4-dimethylphenyl substituent at $R^2$ was the most potent with the $IC_{50}$ values in the range as low as 0.16 to $0.40{mu}M$.