All SCLC CTCs are CD24-positive but lack expression of CD44 and ABCG2 in contrast to the SCLC tumor lines which show a phenotype more similar to that of CSCs.
The immunohistochemical expression of CD24 is associated with worse patient outcomes in small cell lung cancer, hepatocellular carcinoma, breast cancer, and colon cancer.
We conclude that the CD24 promoter has a strong and cell-type-specific activity, and propose its exploitation to drive the expression of therapeutic genes in small-cell lung cancer.