Specific detection of circulating tumor cells by reverse transcriptase-polymerase chain reaction of a beta-casein-like protein, preferentially expressed in malignant neoplasms

Beta-casein-like protein (BCLP) is a putative protein on cervical cancer and exhibits immunological characteristics similar to those of bovine beta -casein. We evaluated if BCLP mRNA detection in the blood is useful in gynecologic malignancies. We examined 30 patients with uterine cancer, nine cultured cancer cell lines and 26 healthy women volunteers. From these study populations and samples, total RNA was obtained. Reverse transcriptase-PCR (RT-PCR) of BCLP was performed on each sample. Eighteen (60.0%) patients and 4 (15.4%) volunteers were positive for BCLP mRNA. The RTPCR reached sensitivity and specificity of 60.0% and 84.6%, respectively. Of eight patients having diagnosed recurrence, 7 (87.5%) were positive for BCLP mRNA. In patients with recurrence, sensitivity and specificity were 87.5% and 50%, respectively. The expression of mRNA showed a correlation with recurrence, but no correlation with metastasis or histological type. BCLP was specifically expressed in cancer cells and might be an aid in clinical diagnosis.