Moreover, the Hsp90 inhibitor 17-AAG and the p38γ inhibitor PFD are both more effective in inhibition of K-Ras MT colon cancer growth in vitro and their combination only has a synergistic growth-inhibitory activity in colon cancer cells harboring a MT K-Ras (Figure 3/4). This evidence concerns the gene HSP90AA1 and malignant colon neoplasm.