Consistent with this, recently we showed that compared to healthy non-smokers, BC from COPD patients show attenuated expression of some transcription factors involved in tissue development and differentiation, which include homeobox (HOX)A1, HOXB2, E74-like ETS transcription factor (ELF3), ELF5 and vestigial like family member (VGLL)1 [16]. Here, HOXA1 is linked to breast cancer.