Figure 1. TOM1L1 is co-expressed with ERBB2 in breast cancer.

(a) The ERBB2 and TOM1L1 loci are frequently co-amplified in breast cancer. Upper part: cumulative array-CGH copy number frequency plots of chromosome 17 in breast tumours with ERBB2 amplification. Copy number gains are in blue, losses in red. Tumours with a log2 ratio higher than the threshold of 0.25 were considered as amplified. Lower part: copy number profiles at chromosome 17 in individual tumours (each line is one tumour). The colour code is the same as in the upper part. About 52.5% of ERBB2-positive tumours show TOM1L1 co-amplification. (b) Representative images showing TOM1L1 protein expression in breast cancer samples with absence (A), weak (B), moderate (C) and strong (D) immunoreactivity. Scale bar, 10 μm. (c) TOM1L1 expression was significantly associated with ER and ERBB2 expression. Histograms shows the results of screening by IHC of TOM1L1 expression in 108 breast tumours encompassing the four major subtypes (ER−, ER+, ERBB2− and ERBB2+). Statistical analysis was done with Student's t-test on raw data. **P<0.01 and ***P<0.001. (d) TOM1L1 is overexpressed in ERBB2+ cell lines. Western blot analyses of TOM1L1, ERBB2 and tubulin (used as loading control) expression in 12 breast cancer cell lines. (e) Kaplan–Meier survival analysis of patients with ERBB2+/ER+ breast cancer from the database of ref. 27. Patients were stratified based on TOM1L1 amplification (red curve) and were compared with patients with no amplification (green curve). The log-rank test was used to determine the statistical significance (P value≤0.05).