Loss of COX-2 resulted in the significant delay of tumor onset when the cells were injected in the mammary fat pad of severe combined immunodeficient (SCID) mice ( Stasinopoulos et al., 2007) consistent with the observation that COX-2 was found to be a part of a gene signature that predicted metastasis of MDA-MB-231 cells to the lung ( Gupta et al., 2007). Here, PTGS2 is linked to neoplasm.