RESULTS: By exploiting the pronounced light-scattering behavior at the smectic-to-chiral nematic transition temperature of 26.5 °C of the vertically aligned CLC, a distinct red–green (signal–background) color contrast was observed in the optical texture of the CLC in the presence of the protein standard bovine serum albumin (BSA) or the cancer biomarker CA125, with the red color intensity correlated positively with the concentration of the biological analyte. The gene discussed is ALB; the disease is cancer.