Figure 2

Comparison of the relative expression of exon 3 deleted estrogenreceptor (ER) variant (ERD3) messenger RNA between breast tumor and adjacentmatched normal breast samples. (A) Total RNA extracted from frozentissue sections from tumor (T) and adjacent normal (N) breast tissue sampleswas reverse transcribed and polymerase chain reaction (PCR) was amplified usingD3U and D3L primers. Radioactive PCR products were separated on a 6% acrylamidegel and visualized by autoradiography. Bands migrating at 354 and 237 basepairs were identified as corresponding to wild-type (WT)-ER and ERD3 variantmessenger RNA, respectively. C, negative control (no complementary DNA addedduring the PCR reaction). (B) For each case, signals corresponding toERD3 variant messenger RNA were quantified and expressed in arbitrary units fortumor (black column) and normal (white column) components. For each sample, themean and the standard deviation of at least three different polymerase chainreaction (PCR) assays are indicated. Cases are sorted by ER status (blackbottom lane) and progesterone receptor (PR) status (gray bottom lane). Samplesthat failed to have three measurable signals in the four experiments performedin both normal and neoplastic components were not included in the statisticalanalysis. The significance of the differences between tumor and normal matchedcomponents within each subgroup, as tested using the Wilcoxon matched-pairtest, is indicated where P <0.05. M, molecular weight marker.