Acid phosphatase in human breast cancer tissue.

When the total acid phosphatase (AP) activity of mammary carcinoma was compared with those of benign pathology and normal mammary tissue the results showed statistically significant differences (P less than 0.05) when expressed per milligram of protein: 358 +/- 42 nmoles per hour (mean +/- standard error) in the malignant tumor, 216 +/- 30 in the benign pathology, and 96 +/- 45 in normal tissue and when expressed per milligram of DNA: 1858 +/- 234, 1227 +/- 140, 695 +/- 345 nmoles per hour, respectively. The polyacrylamide gel electrophoretic profiles showed different levels of isoenzymes 3 and 4 in the three tissue groups. The appearance of isoenzyme 1 is reported after treatment of the homogenates with 5% Triton X-100. It was also found by counterimmunoelectrophoresis that the 28,000 Xg mammary tumor supernatant cross reacts with an antiserum raised against AP isoenzyme 2 although the mammary tissue does not contain such an isoenzyme. To elucidate this point, isoenzymes 1, 3 and 4 were separated by columns of Sephadex G-200 and DEAE-Sephadex. By counterimmunoelectrophoresis, it was observed that only the fraction containing isoenzyme 4 cross-reacted with the antiserum anti-AP isoenzyme 2 maintaining the catalytic activity.