Abstract: The homotopy analysis method is used to obtain semi-analytic solutions for the mathematical model describing a solid tumor growth in the initial a vascular stage of growth. During a vascular tumor growth, the balance between cell proliferation and cell loss determines whether the colony expands or progress. We focus on the chemical inhibition of mitosis within multicell spheroids. The main assumption of modeling the diffusion of a growth inhibitory factor (GIF) within a multicell spheroid and its possible effects on cell mitosis and proliferation