A biochemical characterization of human breast tumors.

The activities of PHI, LDH and LDH isoenzymes were examined in 45 samples of human breast tissue. There were 25 carcinomas, 10 fibroadenomas and 10 nontumor tissue samples. In the group of nontumor breast tissue, values were as follows: PHI (X = 574 SD = 69), LDH (X = 634 SD = 91), LDH5/LDH1 (X = 0.42 SD = 0.23); in the benign group, PHI (X = 425 SD = 95), LDH (X = 59 SD = 188), LDH5/LDH1 (X = 0.55 SD = 0.38); and in the malignant tumor group, PHI (X = 2871 SD = 1350), LDH (X = 3108 SD = 1417), LDH5/LDH1 (X = 3.33 SD = 0.95). The enzyme activities of nontumor and benign tissue were statistically similar, but when these parameters were compared with the enzyme values of malignant tissue, there was a significant statistical difference. Based on these results, it is possible to establish a biochemical criterion for malignancy with the PHI and LDH activity levels greater than 720 U/g and the LDH5/LDH1 ration greater than 1.3. By using this criterion, the examined specimens can be categorized as nontumor or benign in one group and malignant in another group. This corresponds to the histiopathologic system of classification.