Comparisons between NSCLC subtypes showed a significantly higher level of SFRP2 in LCC tumour samples compared to SCC (528.85 vs. 178.18; p = 0.021) and AC (528.85 vs. 116.57; p = 0.004) tumour samples, respectively. Here, SFRP2 is linked to leukoencephalopathy with calcifications and cysts.