Tumor-associated bacteria capable of producing a human choriogonadotropin-like substance.

Aerobic microorganisms were isolated and identified from 9 of 10 malignant tissues aseptically obtained from surgical patients. The organisms isolated are species commonly associated with the flora of the human body. When these cancer-associated organisms were grown in Trypticase soy broth (BBL Microbiology Systems), a protein substance was isolated from the culture filtrates by acetone precipitation. The acetone precipitates of 12 of 14 organisms tested were positive when assayed by radioimmunoassay for the beta subunit of human chorionic gonadotropin (hCG). All but one of the bacterial isolates from the malignancies were capable of producing the hCG-like substance, but in varying quantities. Control organisms (not isolated from a malignancy) and uninoculated Trypticase soy broth were either completely negative in the radioimmunoassay for beta hCG or had levels of beta hCG near the limit of the sensitivity of the method. These results suggest the possibility that bacteria-tumor relationships do exist and are in agreement with the findings of other workers. Investigation of these relationships may have important and provocative implications in the study of neoplastic diseases.