Blood eosinophil and eosinophilic infiltration of tumor tissues in patients with oral squamous cell carcinoma and no allergic diseases were investigated. The patients with blood eosinophilia (>6.0%) were 10/85 (11.8%), and the patients showing increase of % blood eosinophil more than 5% as compared to that of the preirradiated state within 2 months postrirradiation were 20/72 (27.8%). On the other hand, high grade eosinophilic infiltration (>50 cells in 400 field) to tumor tissues was observed in 7/76 of biopsy specimens and in 3/50 of operated materials.
In a case with eosinophilia and eosinophilic infiltration of both biopsy and operated materials, the correlation of eosinophilia with tumor growth and regression was strongly suggested.
These results indicate that although eosinophilia is induced by oral cancer as well as irradiation, tumor cells may produce an eosinophil chemotactic factor (ECF) in tumor-induced eosinophilia.
