To examine whether our RNA-smFISH approach can be applied in cells other than HeLa, particularly for lung carcinomas where AIMP2-DX2 was reported for the first time7, we quantified the AIMP2-DX2/AIMP2 expression ratio in A549 lung adenocarcinoma cells (Fig. 1g, h). Here, AIMP2 is linked to lung adenocarcinoma.