FSTL1 and small cell lung carcinoma: Comparison of human cancer cell lines with a difference in aggressiveness of their phenotype showed opposite outcomes: the prostate cancer cell line LNCaP shows lower FSTL1 expression levels compared to the more aggressive C4-2 variant [17], while less aggressive non-small cell lung carcinoma (NSCLC) cells express on average higher levels of FSTL1 compared to more malignant small cell lung cancer (SCLC) cells [67].