Aziz Sancar, Nobel Prize winning Turkish scientist, made several discoveries which had a major impact on molecular sciences, particularly disciplines that focus on carcinogenesis and cancer treatment, including molecular pathology. Cloning the photolyase gene, which was the initial step of his work on DNA repair mechanisms, discovery of the “Maxicell” method, explanation of the mechanism of nucleotide excision repair and transcription-coupled repair, discovery of “molecular matchmakers”, and mapping human excision repair genes at single nucleotide resolution constitute his major research topics. Moreover, Sancar discovered the cryptochromes, the clock genes in humans, in 1998, and this discovery led to substantial progress in the understanding of the circadian clock and the introduction of the concept of “chrono-chemoterapy” for more effective therapy in cancer patients. This review focuses on Aziz Sancar’s scientific studies and their reflections on molecular pathology of neoplastic diseases. While providing a new perspective for researchers working in the field of pathology and molecular pathology, this review is also an evidence of how basic sciences and clinical sciences complete each other.