Two of the 51 mAbs, however, did inhibit coalescence in the screen, and did so completely, H4C4 against CD44, the hyaluronic acid receptor, and AIIB2, against beta-1-integrin (CD29), the mAb previously demonstrated to block coalescence of tumorigenic breast tumor-derived cells [18, 19]. This evidence concerns the gene CD44 and breast neoplasm.