LO2 cells originated from a lung metastasis in a 72 year old male with colorectal cancer. The cell line was established by subcutaneous inoculation into BALB/c nude mice and passaged for 23 times. In the course of passage in nude mice, the tumor still retains the histological characteristics of the original colorectal cancer. The formation of monolayer confluent state cell line X, between adjacent cells are closely connected and desmosome; the cells have a variety of peptide hormones and neurotransmitter receptors, maintain the directional transport of electrolyte; cytokeratin positive.