Some lung carcinoma tissues produce unusual alkaline phosphatases (APs), the Regan, Nagao and other on-codevelopmental isoenzymes which are usually absent in normal lung tissue. The aim of this study is to characterize these enzymes in lung carcinoma and to find any relation of the AP isoenzymes to cell types of lung carcinoma.
The properties of AP isoenzymes of lung carcinoma tissue from 30 cases were examined in comparison to counterparts in 8 normal lungs, and normal liver and placenta.
The specific activity of AP in the lung carcinoma tissue of case S.M., one of the 30 cases, was about 60 times as high as the average AP activity of the 8 normal lungs. The average specific activity of the remaining 29 cases of lung carcinoma was also significantly higher than that of normal lung AP. Among lung carcinoma, cases, the average specific activity of the adenocarcinoma group was higher than that of squamous cell carcinoma group. However exclusion of case S.M. from the adenocarcinoma group resulted in almost equal specific activity in the two groups. The specific activity of anaplastic carcinoma was the lowest.
The AP of the case S.M. electrophoresed slightly faster than that of normal lung but slightly slower than liver AP. The AP from 29 carcinomatous tissues showed microheterogenous electrophoretic mobilities with broad bands, ranging from liver AP to bone AP to bone AP band. Treatment of enzyme preparation with neuraminidase made it clear that two out of 29 lung carcinomas had another faster migrating band, identified as Regan isoenzyme. The other 27 cases had an enzyme, “usual lung type AP”, which was indistinguishable in properties from counterparts of normal lung, normal liver, and early placenta. The isoenzyme of lung carcinoma from case S.M., also belonged to the usual lung type AP.
