What would cause jaundice and slightly elevated AFP levels in a leukemia patient?

My 2 1/2 year old boy had a stage 1 FH Wlims' Tumour as an infant, NED status in February 2007. He had a nephrectomy and 18 weeks of chemo. Diagnosed with secondary AML leukemia in December 2008. He's in remission right now and in between consolidation chemotherapy rounds right now. He seems to have a good level of energy and feels good. Why might he have slightly elevated AFP levels and be jaundiced?