Though there has been criticism concerning SPF values due to its inability to distinguish cells that were actively synthesizing DNA from the putative S-quiescent cells [66], SPF has been considered to be the most useful cell proliferation method in predicting the short-term prognosis of patients with cancer [37], with the conventional median SPF category being the best indicator of disease outcome compared with other SPF variables and the Ki-67 index. Here, MKI67 is linked to cancer.