Table 3.

Summarizing the important proteins involved in steroids and arachidonate metabolism in TMZ-resistant GBM

Protein	Function	Role in TMZ resistance
Cytochrome P450 enzymes	Family of enzymes involved in metabolism of steroids, drugs, and other compounds	CYP17A1 and CYP19A1 have been implicated in TMZ resistance in GBM [48–50]
Prostaglandin E synthase	Enzyme that catalyzes conversion of prostaglandin H2 to prostaglandin E2	Upregulation observed in TMZ-resistant GBM cells [44]
5-Lipoxygenase	Enzyme that catalyzes conversion of arachidonic acid to leukotrienes	Expression shown to be upregulated in TMZ-resistant GBM cells [51]
Androgen receptor	Nuclear receptor that regulates expression of genes involved in tumor malignancy	Activation promotes TMZ resistance in GBM; inhibition sensitizes GBM cells to chemotherapy [52]