The interaction between Herceptin and SK-OV-3 cells (a human ovarian carcinoma cell line) was recently investigated using this approach28 and we used the QCM-based system to study Herceptin binding to the HER2-over-expressing breast cancer cell line SKBR-329 as well as to recombinant HER2 (rHER2) protein and to evaluate the effect of deglycosylation on Herceptin binding. The gene discussed is ERBB2; the disease is ovarian carcinoma.