k‐means clustering analysis of these data alongside RNAseq datasets from unrelated cell types (NIH/3T3 fibroblasts (Wang et al, 2017), MDA‐MB231 metastatic breast cancer cells (Mardakheh et al, 2015), induced neuronal cells (Zappulo et al, 2017)) revealed unexpected cell type‐specific diversity to transcript polarisation, with only five mRNAs exhibiting universal targeting to protrusions in all cell types tested (cluster k 5; RAB13, TRAK2, RASSF3, NET1, KIF1C; Figs 1B and C, and EV1A). This evidence concerns the gene TRAK2 and breast carcinoma.