Table 2.

Classification of lncRNAs.

Genomic Location	Description	Example
Intergenic	transcripts originated from intergenic loci; that is, located between two protein-coding genes	XIST, NEAT1, PANDAR, BGLT3
Intronic	transcripts originated from introns of protein-coding genes	NDM29, IRAIN, EGOT
Sense	transcripts originated from the sense strand of protein-coding genes, containing exons from protein-coding genes	SNHG3, SRA, RUNXOR
Antisense	transcripts originated from the antisense strand of protein-coding genes	SNHG6, HOXA-AS2, ZEB2-AS1
Enhancer	transcripts, found in both polyadenylated or non-polyadenylated forms, bi-directionally expressed at active enhancer regions of the genome	DLX6-AS1, Alpha-250/Alpha-280, LUNAR1
Promoter	transcripts derived from gene promoter regions in the opposite direction to the paired coding RNA	DBET, pancIl17d, HIF2PUT