Figure 1.

16q23 gain associated with breast cancer (BC) bone metastasis. A) In vivo selection of subsequent bone metastatic derivatives from MCF7 parental cell line with representative bioluminescent images. Kaplan-Meier curve shows bone metastasis–free survival for parental or BoM2 cells injected via left ventricle. P value was obtained using two-sided log-rank test. B) Comparative genomic hybridization (CGH) analysis for Chr 16 compares BoM2 with MCF7 parental cells. Black dots and blue horizontal lines represent normalized log2 intensity ratios and segments, respectively. Red bar underlines 16q22-24 DNA genomic gain and CEN centromeric region. C) Analysis of copy number aberrations on the basis of gene expression (ACE-like Algorithm) for Chr 16. Genomic areas of statistically significant association of increased gene expression with metastasis in estrogen receptor–positive (ER+) BC tumors (discovery MSKCC/EMC dataset) and validation (van de Vijver dataset) are colored. Solid red line indicates differences in gene expression; dashed red line indicates the expected lack of variation between populations. D) Representative images of florescence in situ hybridization (FISH) analysis in BC cell lines with the indicated probes. Scale bar = 10 μm. E) Top, FISH image of patient sample without 16q23 gain (16q23/CEP16 < than 1.5 copies), and bottom, patients with 16q23 gain (16q23/CEP16> than 1.5 copies). Scale bar = 10 μm. F) Cumulative incidence plot of bone metastasis at anytime, using death before recurrence in bone as a competing event for all (left) and ER+ primary tumors (right) in Spanish dataset (n = 334, n = 250 respectively). Patients were stratified according to 16q23/CEP16 ratio per cell, as CNA-negative (<1.5) and 16q23/CEP16 CNA-positive (> or = 1.5). A minimum of 50 cells per core and three cores per tumor were scored. P values were obtained after fitting Cox proportional hazards model with competing events. BC = breast cancer; CI = confidence interval; ER = estrogen receptor; HR = hazard ratio.