Recently it was shown that during lung cancer development Nkx2.9 interacts with Nkx2.1 and Pax9 [42], and while these two factors are not expressed in mdDA (precursor) neurons, it is possible that Nkx2.9 maintains a similar molecular relationship in mdDA neurons with other (yet unknown) transcription factors. The gene discussed is NKX2-1; the disease is lung carcinoma.