Table 2.

Classification of lncRNAs

Classification	Description	Example
Intergenic	produced by the transcription of spacer sequences between genes encoded in the genome	XIST, TMEM161B-AS, HAR1, NEAT1, TUG1
Intronic	transcribed from introns within a protein-coding gene	Lnc-OR51B4-3, KCNIP4-IT1
Sense	transcribed from the coding strand of a protein-coding gene and partly or completely overlapping the gene exons	SNHG4
Antisense	transcribed from the non-coding strand of a gene	BACE1-AS, MALAT1, lnc-LRR1, TUSC7
Bidirectional	transcribed from the promoter region in two opposite directions	Hoxa11as, IGF2AS, HOTAIRM1