Our study is the first report that involves the characterisation of somatic variants of ROBO1.IG1, ROBO4.IG1-2 and SLIT2.D2 domains reported in various cancers including lung cancer, and their role in domain-domain interactions of the receptors (ROBO1.IG1 and ROBO4.IG1-2) and the ligand (SLIT2.D2). The gene discussed is SLIT2; the disease is lung cancer.