Cancer begins at a tiny genetic level inside cells, causing biochemical changes that escape detection until the disease appears. Biochemistry helps by measuring tumour markers like PSA, CA-125, and CEA in blood, which flag cancers early. Enzyme tests show cancer burden, and advanced assays detect tiny remaining cancer cells. Biochemists monitor treatment effects and spot life-threatening complications. Microbiology identifies cancer-causing microbes such as HPV and Helicobacter pylori and manages infections in weakened cancer patients using rapid techniques like BACTALERT and MALDI TOF. Early detection preserves effective antibiotic use and prevents resistant infections. Pathologists confirm cancer by examining biopsies under microscopes and through molecular tests. They define cancer type, grade, and genetic traits to guide targeted and immunotherapies. Oncopathologists also identify precancerous changes, assist surgeons during operations, and monitor treatment response and relapse. Together, biochemistry, microbiology, and pathology provide the unseen backbone for cancer diagnosis, personalized treatment, and survival monitoring, offering patients hope through science and technology.