In step I, we selected 11 lncRNAs (PCAT‐1, SPRY4‐IT1, MALAT1, UCA1, TUG1, UBC1, GHET1, H19, SNHG16, MEG3 and BC039493) as candidate targets, which have been previously reported to be differently expressed in BC tissues.21, 22, 23, 24, 25, 26, 27, 28, 29, 30 In step II, we quantified the expressions of 11 candidate lncRNAs from serum exosomes in 50 BC patients and 50 controls using the qRT‐PCR. The gene discussed is PCAT1; the disease is breast cancer.