Fig. 3.

Stathmin is a marker of the PTEN/PI3K signature. (A) Immunoblotting analysis of relative protein levels for four selected signature genes across a panel of eight BC cell lines. (B) Box plots illustrating stathmin IHC scores to be significantly higher in PTEN^IHC− vs. PTEN^IHC+ breast tumors among all 181 cases analyzed for both proteins (Left) and within the subgroup of 62 ER-negative cases (Right). P values were calculated by using the Mann–Whitney test. (C) Stathmin IHC levels are highly correlated to the presence of the PTEN/PI3K signature (ROCarea = 0.809, P < 0.0001). The hierarchical clustering tumor dendrogram, marker annotations, and STMN1 (represented by two independent reporters) and PTEN message levels are from Fig. 1 B and C. Stathmin IHC scores are centered to the median score, 6 (white boxes), with higher and lower scores colored in red and blue, respectively (key to right). (D) Scatterplot analyses show stathmin IHC levels to closely track STMN1 mRNA levels (average of the two reporters) and to be significantly inversely related to PTEN mRNA levels. Linear regression and the Pearson correlation r and P values are presented. (E) KM analysis indicates stathmin-high (score >10) tumors have a significantly higher rate of distant disease recurrence compared with stathmin-low (score 0–10) tumors among 191 BCs analyzed. Log-rank P values for complete follow up (top right corner) and the 2- and 5-year intervals are shown. Cox regression analysis is presented in SI Table 5. Representative stathmin IHC examples are presented in SI Fig. 10.