CD44 VARIANT ISOFORM EXPRESSION AND BREAST-CANCER PROGNOSIS

We examined the expression of CD44 isoforms in samples of breast cance r tissues from 95 patients by reverse transcription-polymerase chain r eaction and immunohistochemistry, and tried to correlate the results w ith survival period, At the RNA level, expression of exon v2 was obser ved in 33 (35%) and that of v6 in 69 (73%) of the 95 specimens, Patien ts with CD44v2 mRNA expression had significantly shorter survival time s than those with v2-negative tumors (P=0.05), but there was only a we ak correlation, if any, between v6 mRNA expression and overall surviva l (P=0.06). Tumor tissue from 22 (23%) and 72 (76%) patients showed po sitive immunoreactivity with monoclonal antibody (mAb) M23.6.1. (CD44v 2) and mAb 2F10 (CD44v6), respectively, Immunohistochemical evidence o f CD44v2 peptide expression correlated with overall survival (P=0.02), but there was no such association with CD44v6 expression in these tum ors (P=0.67). There were significant correlations between v2 immunorea ctivity and higher histological grade and lower levels of estrogen and progesterone receptor, There was no significant correlation between v 6 immunoreactivity and such clinicopathological characteristics. Altho ugh the expression of v2 was significantly associated with reduced ove rall survival, it was not an independent prognostic factor because it also correlated with progesterone receptor status, These findings sugg est that v2 isoform expression might have more value than v6 expressio n for clinical use.