Correlation Between Tumor Invasiveness and Content of A-Type Particles in Ehrlich Ascites Tumor: A Model of Quantitative Electron Microscopy

Abstract

The ultrastructure of Ehrlich ascites tumor in mice in relation to tumor invasiveness was investigated. Of the 4 hypotetraploid clones and 1 hyperdiploid stock tumor, the incidence of intracisternal A particles in tumor cells increased with tumor invasiveness (an inverse of survival time of mice), and the correlation was statistically significant. The number of A particles in a single tumor cell, calculated by stereologic rearrangement of data, ranged fromthe minimum value of 101 for Ehrlich 2N tumorto the maximum value of 15,600 for clone 4 (4N). The incidence of A particles in normal tissues (thymus, liver, and lactating mammary gland) was much lower than that of any neoplastic cells tested. The three-dimensional conversion of the electron micrographs was based on the assumed “geometric thickness of the section,” which actually accounted for the particle counts observed.