MCF-7 and MDA-MB-231 breast cancer cells, which have different expression levels of the three protein markers, were stained with sb-UCNP-Abs bioconjugates (sb-UCNPs-Anti-PR (green), sb-UCNPs-Anti-ER (blue) and sb-UCNPs-Anti-HER2 (red)). The gene discussed is PGR; the disease is breast cancer.