Immunocytochemical demonstration of calmodulin and its activated forms in normal and carcinomatous human mammary...

Using an indirect immunoperoxidase technique with a polyclonal antibody (CaMp) for calmodulin (CaM) and monoclonal antibodies against CaM activated form of cyclic nucleotide phosphodiesterase (ACAP-1) and calcium activated CaM (ACC-1), we have investigated the distribution pattern of this calcium-binding protein on frozen and paraffin sections of ductal non-infiltrating (20 cases) and infiltrating carcinomas (39 cases), lobular in situ (3 cases) and infiltrating carcinomas (8 cases); 10 metastatic axillary lymph nodes were also studied, while normal breast tissue surrounding neoplasias was tested as a control. All cases of non-infiltrating as well as infiltrating ductal and lobular carcinomas were reactive with the above-mentioned antisera, although a marked variation both in the proportion of cells stained within a tumour and in the intensity of staining of the cells was noted; the immunoreactivity showed a diffuse cytoplasmic pattern but sometimes nuclear with CaMp and ACC-1, while ACAP-1 exhibited mostly a cytoplasmic perinuclear granular expression; the same immunohistochemical pattern for CaM and CaM activated forms was observed also in metastatic elements present in axillary lymph nodes. Normal breast acini were patchily reactive for ACAP-1, whereas CaMp and ACC-1 stainings were more diffuse.