Cancer is an active killer worldwide. The cancer incidence has been on a rising trend, increasing at an average rate of about 3.1% per year in the past decade. This alarming trends stimulate Mr. Liu Mingkang's interest in cancer research. All research projects bring unexpected difficulties. In his case, the experiment lacked clear selection criteria for the desired single cell clones which is one of the core questions to be solved in his research project. Then, Mingkang consulted experienced professionals. Then he attempted to optimise the experiment conditions, and patiently screened multiple colonies with varied selection marker expressions. Eventually, Mingkang successfully developed the genetically modified cell model and hope no one would suffer from the untreatable disease in the world.