CST3 and cancer: However, eGFR calculatedusing an alternative marker of kidney function (cystatin C—not routinelytested or available for comparison in this population) shows a more biologicallyplausible, linear association between eGFR and cancer death [8], suggesting that the J-shapedrelationship with eGFRCr reflects flaws in creatinine-basedestimation of kidney function.