To determine whether CNPY3 is required for human breast cancer cell growth and metastasis in vivo, we performed a human breast cancer xenograft model by implanting WT control and CNPY3 KO MDA-MB-231 breast cancer cells into the fourth mammary gland in NSG mice and monitored tumor growth, endpoint survival, and metastasis. The gene discussed is CNPY3; the disease is neoplasm.