The clinical usefulness of BRCA1 and BRCA2
mRNA levels in
tumor tissues in the prediction of response to
docetaxel (DOC) treatment has been studied in
breast-cancer patients. Twenty-five patients with locally advanced
breast tumors (n = 13) or locally recurrent
tumors (n = 12) underwent
tumor biopsy and were treated with DOC (60 mg/m2 every 3 weeks). BRCA1 and BRCA2
mRNA levels in the
tumors were determined by real-time PCR, and the expression of 6
biological markers (
P-glycoprotein, p53, erbB2, BCL2, MIB1,
estrogen receptor-alpha) in the
tumors was determined by immunohistochemistry. BRCA2
mRNA levels (0.547 +/- 0.200, mean +/- SE) of responders to DOC treatment were significantly (p < 0.05) lower than those of non-responders (1.538 +/- 0.358), but there was no significant difference in BRCA1
mRNA levels between responders (0.389 +/- 0.081) and non-responders (0.779 +/- 0.172).
Tumors were dichotomized into groups with high or low BRCA2
mRNA levels according to the cut-off value of 0.13. The response rate (25%) of
tumors with high BRCA2
mRNA levels was significantly (p < 0.01) lower than that (100%) of
tumors with low BRCA2
mRNA levels. Positive predictive value, negative predictive value and diagnostic accuracy of the BRCA2
mRNA assay in the prediction of response to DOC were 100%, 75% and 80%, respectively. No significant difference was found between responders and non-responders in the expression status of any of the other 6
biological markers. These results suggest that BRCA2
mRNA levels in
tumor tissues might be clinically useful in the prediction of response to DOC treatment in
breast-cancer patients.