His scientific interests lie mostly in Internal medicine, Glioma, Genetics, Cancer research and Odds ratio. His Internal medicine research incorporates themes from Endocrinology, Oncology and Pathology. His study in Glioma is interdisciplinary in nature, drawing from both Genome-wide association study, IDH1 and Isocitrate dehydrogenase.

He combines subjects such as Carcinogenesis, Methylation, Telomerase and DNA methylation with his study of Cancer research. John K. Wiencke has researched DNA methylation in several fields, including DNA microarray and Cellular differentiation. The study incorporates disciplines such as Cancer and Case-control study in addition to Odds ratio.