Single nucleotide mutations, including polymorphisms of epidermal growth factor receptor (EGFR), KRAS proto-oncogene, GTPase (KRAS), and rearrangements of the ALK receptor tyrosine kinase (ALK) gene, are also involved in the occurrence of low-grade metastatic adenocarcinoma-type lung cancer [17]. Here, NTRK1 is linked to lung cancer.