ENPP2 and breast cancer: In the transgenic mice that overexpress ATX or LPA1-3 under the MMTV-LTR promoter [52], the spontaneous development of mammary tumors displayed late onset, ranging from 8 to 24 months, and occurred in a subpopulation of each transgenic mouse strain, suggesting that expression of ATX and LPA receptors cooperates with other events, such as secondary mutations, to generate the full tumorigenic phenotype [52].