[Use of immunohistochemistry in detecting the primary site in neoplasm metastasis]

The aim of the present study is to demonstrate the sensitivity, specificity and applicability of several tissue markers in the determination of the primary sites of metastatic tumors. The immunoperoxidase technique was used in 19 metastatic tumors from breast (6), gastrointestinal tract (6), thyroid (3), prostate (1), ovary (1), pancreas (1) and melanoma (1). Polyclonal antisera against thyroglobulin and prostatic specific antigen were used. The following monoclonal antibodies were employed: BRST-1, BRST-2, CAR-3, BD-5 and HMB-45. BRST-1 and BRST-2 are considered to be breast cancer markers, while CAR-3 and BD-5 gastrointestinal markers. HMB-45 was described as a melanoma marker. Breast markers were positive for 3 out of 6 breast metastases. BRST-1 was also positive for metastases from melanoma and prostate. CAR-3 and BD-5 were positive for 5 out of 6 gastrointestinal metastases. CAR-3 also presented focal positivity for 4 out of 6 breast metastasis, 1 out of 3 thyroid metastasis and for metastasis from ovary, prostate, pancreas and melanoma. BD-5 was also positive for prostate metastasis. Thyroglobulin and prostatic specific antigen were only positive for thyroid and prostate metastasis, respectively. In conclusion, immunocytochemistry and monoclonal antibodies are useful tools in the detection of the primary sites of metastatic tumors of unknown origin. In some of the fields, the results are already satisfactory. Nevertheless, further studies should be carried out to improve this promising technique.