Fluorescence polarisation changes in lymphocyte cytoplasm as a diagnostic test for breast carcinoma

Lymphocytic cytoplasm from individuals with malignant disease, and from those without, differ in such a way as to be diagnostic both of malignancy generally and of specific types of cancer. Mitogenic stimulation of lymphocytes by phytohaemagglutinin (PHA) and antigenic stimulation by encephalitogenic factor (EF) and certain specific tumour-associated antigens, provokes changes in the structure of the cytoplasmic matrix (SCM) which are detectable upon fluorescence polarisation. The degree of change is quantifiable both by calculating the polarisation ratio (PR, polarisation before and after stimulation) and the relative ratio (RR_SCM, the ratio between the polarisation obtained after exposure to EF [P_EF] and to the polarisation measured after exposure to PHA [P_PHA]). A new tumour-associated antigen specific for breast cancer, CaBr, was tested for its diagnostic efficacy in comparison with that of EF, by prospectively testing blood samples from 138 consecutive women with suspicious breast masses. The previously known discriminatory power (sensitivity 60.7% and specificity 90.7%) of the polarisation-derived RR_SCM was reconfirmed. However, the RR'_SCM (the new ratio using CaBr instead of EF), was significantly more sensitive (77.4%; P < 0.01) and specific (94.4%) than the RR_SCM in detecting breast cancers. The polarisation changes in the cytoplasmic matrix after stimulation by CaBr alone suggest the best discriminatory power (sensitivity 90.5% and specificity 94.4%) between cancerous and non-cancerous patients.