Hyaluronan is critical for forming the extracellular matrix and mediating cell to cell interactions.10,11 Hyaluronidases are responsible for degrading hyaluronan; thus, they play important roles in cancer progression.12 The family of hyaluronidases includes Hyal-1, Hyal-2, Hyal-3, Hyal-4, PH20, and a pseudogene in the human genome.13 Hyal-1, Hyal-2, and PH20 have hyaluronidase activity for hyaluronan hydrolysis.14 The hyaluronidase family members have different expression profiles in different cancers. This evidence concerns the gene HYAL4 and cancer.