[Light and electron microscopic examination compared to evaluation by tumor size in subrenal capsule assay for chemosensitivity testing in esophageal cancer].

Specimens from six clinical cases of esophageal cancer were transplanted under the renal capsule of AF nude mice, and chemosensitivity to anticancer drugs (UFT, CDDP) was evaluated by measuring tumor size (SRC). Histological analysis of the xenografts by light (LM) and electron microscopy (EM) was also performed to confirm the precision of this original method used for SRC. Two-dimensional morphometry by EM was also performed in four cases. With the exception of one case, the same results were obtained by graft measurement analysis and light microscopic observation, which allowed easy evaluation by observing cancer pearl formation, prominent proliferation of tumor cells or total cell keratinization. However, there was no false-positive sensitivity in the former method. EM observation did not reveal any special findings with regard to chemotherapy response, but increased numbers of cytoplasmic vacuoles and desmosomes, cytoplasmic swelling, a reduction of the N/C ratio and nuclear deformity implied common changes to cell necrosis induced by the anticancer drugs. For clinical use of SRC against esophageal cancer, it is supposed to be best to compare LM histological evaluation, which is too complicated and time consuming. For this reason, it is potentially useful to perform SRC by evaluating tumor size, because another goal of chemosensitivity testing involves determination of anticancer drugs without effectiveness.