TABLE 1.

The mechanisms of m6A writer in regulating BC progression.

Regulators	Expression pattern	Functions and mechanisms	Ref
METTL3	Low expression in TNBC	the low expression of METTL3-reduced m6A modification could promote TNBC metastasis by up-regulating COL3A1	(18)
METTL3	Upregulation in BC tissue, especially in T3-T4 or those accompanied with lymphatic metastasis	METTL3 promoted the stemness and malignant progression of BCa through mediating m6A modification on SOX2 mRNA	(19)
METTL3	Upregulation in BC tissue and cells	METTL3 knockdown could decrease the methylation level, reduce the proliferation, accelerate the apoptosis and inhibited the tumor growth by targeting Bcl-2	(20)
METTL3	Upregulation in BC tissue	HBXIP up-regulated METTL3 by suppressing let-7g, in which METTL3 increased HBXIP expression forming a positive feedback loop of HBXIP/let-7g/METTL3/HBXIP, leading to accelerated cell proliferation in BC	(21)
METTL3	Upregulation in BC tissue and cells	Silencing METTL3 down-regulated MALAT1 and HMGA2 by sponging miR-26b, and finally inhibited EMT, migration and invasion in BC	(22)
METTL3	−/−	METTL3 increased the m6A methylation of LINC00675, which enhanced the association between LINC00675 and miR-513b-5p	(23)
METTL3	−/−	MicroRNA-135 inhibited initiation of EMT in BC by targeting ZNF217 and promoting NANOG m6A modification	(24)
METTL3	Decreased in TNBC tissues and cell lines	circMETTL3 could act as a sponge for miR-34c-3p and inhibits cell proliferation, invasion, tumor growth and metastasis by up-regulating the expression of miR-34c-3p target gene METTL3	(26)
METTL3	−/−	circMETTL3 promotes BC progression through circMETTL3/miR-31–5p/CDK1 axis.	(27)
METTL14	Upregulation in BC cells and BC cohorts	LNC942 promoted METTL14-mediated m6A methylation in BC cell proliferation and progression	(29)
METTL14	Low expression in BC	LncRNA UCA1 promoted SOX12 expression by regulating m6A modification of miR-375 by METTL14 through DNA methylation	(30)
METTL14	Upregulation in BC tissue	METTL14 modulated m6A modification and hsa-miR-146a-5p expression, thereby promoting the migration and invasion of BC cells	(31)
METTL5	Elevated expression in BC tissue and cell lines	Ribosome 18S m6A methyltransferase METTL5 promotes translation initiation and BC cell growth, uncovering critical and conserved roles of METTL5 in the regulation of translation	(33)
KIAA1429	Overexpression in BC	KIAA1429/SMC1A/SNAIL axis in promoting EMT progress and metastasis in BC	(35)
KIAA1429	Highly expressed in BC tissues	KIAA1429 promoted BC progression and was correlated with pathogenesis by associating with CDK1 mRNA in an m6A-independent manner.	(36)