To further understand the role of PHGDH in tumor growth and maintenance in vivo, nude mice were injected subcutaneously with MDA-MB-468, HCC1806 or BT-20 cells expressing Doxycycline-inducible shRNA to PHGDH. In the MDA-MB-468 xenograft mouse model, one PHGDH shRNA showed some growth effects, but this didn't correlate with PHGDH knockdown, raising the concern that the growth effect observed was due to off target of this hairpin in the 468 cell line (Fig. 4A and B). This evidence concerns the gene PHGDH and neoplasm.