Figure 3.

Functional assessment of in-frame expressed fusion genes. To determine the biological significance of the in-frame fusion genes identified in MPCs, forced expression of each fusion gene (SLC2A1–FAF1, A and BCAS4–AURKA, B), the 3′ partner gene, and an empty vector was performed in a panel of breast cancer cell lines. The fold change in cell population (y-axis) is plotted against growth time (days, x-axis). Red, solid black, and dashed black lines denote growth curves following transfection with fusion gene constructs (ie SLC2A1–FAF1 or BCAS4–AURKA), full-length 3′ partner genes (ie FAF1 or AURKA), and empty vector (pCMV), respectively. Western blotting using anti-DDK antibody was employed to confirm exogenous expression of cDNA constructs following transfection in MCF7 cells (A and B). In A and B, statistically significant differences are highlighted with an asterisk. (C) A matrix illustrating the pathological phenotype and aberrations affecting endogenous fusion gene partners in the cell lines employed, where dark blue squares represent positivity in a marker, light blue squares represent negativity in a marker, green squares denote amplification of a gene, and red denotes rearrangement of a gene.