IIGP1 was chosen to validate the microarray results concerning the host immune defense against parasite infection, IDO1, SPP-1 and UBD for the progression of tumor microenvironment, and DEFA1 and DEFA3 for the anti-microbial response speculated to be suppressed by C. parvum in order to propagate cancer. The gene discussed is IDO1; the disease is cancer.