PTGS2 and neoplasm: Our study indicated that C-phycocyanin in triple-negative breast cancer MDA-MB-231 cells (i) inhibits the proliferation of tumor cell (ii) induces tumor cell cycle G0/G1 arrest (iii) promotes tumor cell apoptosis through the cell membrane surface death receptor (exogenous) pathway (iv) inhibits the COX-2 expression and tumor cell metastasis (v) down-regulates ERK signaling pathways and up-regulates JNK and p38 MAPK signaling pathways to induce tumor cell death (Fig. 7).