Comparing control and GNA13 stable expressing cells, we found that, in contrast to the ER+ cells as shown above, exogenous expression of GNA13 in these ER- cells had no impact on cell proliferation (Fig. 2E and F), suggesting that the effect of Gα13 on cell proliferation could be specific to ER+ breast cancer subtype. This evidence concerns the gene GNA13 and breast carcinoma.