The detection of micrometastases in the peripheral blood and bone marrow of patients with breast cancer using immunohistochemistry and reverse transcriptase polymerase chain reaction for keratin 19.

The aim of this study was to determine whether reverse transcriptase polymerase chain reaction (RT-PCR) for keratin 19 (K19) provides additional information when combined with immunohistochemistry when used to detect micrometastases in blood and bone marrow in patients with primary breast cancer. We studied 78 patients with breast cancer who had no evidence of distant metastases. We collected blood and bone marrow, separated the mononuclear fraction and carried out RT-PCR and immunohistochemistry for K19. RT-PCR was done by two 40-cycle rounds using nested primers. In initial experiments, RT-PCR was shown to be capable of detecting one tumour cell in one million normal bone marrow cells, which was at least 10 times more sensitive than immunohistochemistry, while retaining specificity. Five per cent of the peripheral blood and 22% of the bone marrow samples contained K19 positive cells by immunohistochemistry staining. Using RT-PCR, these proportions increased to 25% and 35%, respectively. This represents a significantly greater detection frequency (P < 0.001 and P = 0.03, respectively). RT-PCR for K19 is a more sensitive method for detecting micrometastases in patients with primary breast cancer when compared with immunohistochemistry.

Expression of ecto-5'-nucleotidase (CD73) in normal mammary gland and in breast carcinoma.

Ecto-5'-nucleotidase (ecto-5'-NT) is a phosphatidylinositol anchored membrane structure recently defined as the lymphocyte differentiation antigen CD73. Using CD73 (1E9.28.1) monoclonal antibody, normal mammary gland and breast carcinoma were immunohistochemically investigated for ecto-5'-NT expression. In normal breast epithelium, CD73 was differentially expressed in lobular, ductal and myoepithelial cells and was most frequently detected in the myoepithelial compartment. The glandular stroma contained fibrocytes, a subset of which was also CD73-positive. Among 102 unselected breast carcinoma primary lesions, only 9 contained CD73-positive tumour cells, whereas in 95 cases, stromal fibroblasts and fibrocytes showed variable degrees of CD73 expression. The extent of stromal CD73 expression correlated positively with the estrogen receptor (ER) status of the tumour (P less than 0.038). We conclude that ecto-5'-NT-expression reflects a still unknown state of activity of normal breast epithelium which is lost in the majority of carcinomas derived therefrom. It may also be indicative of some functional activity of stromal fibroblasts which is significantly enhanced in ER-positive carcinomas.

Antigenic profile of mammary fibroadenoma and cystosarcoma phyllodes. A study using antibodies to estrogen- and progesterone receptors and to a panel of cell surface molecules.

Using serial frozen sections, monoclonal antibodies and an indirect immunoperoxidase method, 13 fibroadenomas (FA) and 3 cystosarcomas phyllodes (CSP) were analyzed for the expression of Egp34, HEA319-antigen, leucocyte differentiation antigens CD10, CD30, CD57, CD72, CDw75, and CD77, epidermal growth factor receptor (EGFR), estrogen (ER) and progesterone receptor (PR), and transferrin receptor (CD71). Egp34, CDw75, HEA319 antigen, CD10, and CD30 turned out to be consistently expressed in different cell types constituting FA and CSP and revealed that in malignant CSP the myoepithelial compartment acquires the ability to invade the stroma. Phenomenologically, the variable mode of expression of CD57 in myoepithelial cells, of CD77 in ductal epithelium, and of CD72 in both epithelial and stromal cells is suggestive for reflecting differences in their functional state but cannot be further interpreted at present. Expression of PR and ER was restricted to duct cells and was relatively independent, non-systematical. However, expression of ER and EGFR was inverse. This was also true for EGFR and CD71 in both duct cells and myoepithelial cells of FA. In contrast, stromal cells of FA were able to co-express EGFR and CD71 in the absence of PR and ER. This suggests a hormone-independent stimulation of the stromal cell compartment, possibly leading to local proliferation as the primary event in tumorigenesis of FA. In malignant CSP, however, the main proliferating cell is an abnormally mobile, HEA319 antigen-, CD10- and CD30-positive myoepithelial cell found to co-express ERFR and CD71 which is abnormal for this cell type but encountered in (myo-)fibroblasts of FA.