CD44 and neoplasm: Our immunohistochemical study, showing that the tumors with a high P/C ratio for CD44 contained much more GSCs expressing CD44 in the tumor periphery compared with those with a low P/C ratio for CD44, may suggest that there are many more GSCs in the microenvironment with upregulating CD44 expression on GSCs than those in the microenvironment without stimulation for CD44 expression.