H19 and lung cancer: In lung cancer, butyrate-producing microbial communities were found to upregulate genes related to H19, a long non-coding RNA (lncRNA), by inhibiting histone deacetylase 2 (HDAC2), thereby promoting histone H3 lysine 27 acetylation (H3K27 acetylation) and enhancing H19 promoter activity [102].