Table 1 Wnt ligands and related factors in breast cancer

Wnt1

Canonical

Activated by MMTV integration in breast cancer;

Activated by TP53 loss in breast cancer;

Highly expressed in breast cancer

[3, 5, 24,25,26]

Wnt2

Canonical

Expressed at a high level in breast cancer

[27,28,29,30,31,32]

Wnt2b

Canonical

–

[33, 34]

Wnt3

Canonical

Overexpressed in trastuzumab-insensitive breast cancer cells;

Activated by TGFβ in breast cancer cells

[35,36,37]

Wnt3a

Canonical

Amplified in breast cancer

[16]

Wnt4

Noncanonical

Driven by estrogen and progesterone in breast cancer

[25, 27, 38, 39]

Wnt5a

Canonical/noncanonical

Highly expressed in BLBC

[15, 16, 22, 40]

Wnt5b

Canonical/noncanonical

Highly expressed in BLBC

[16, 22, 41,42,43]

Wnt6

Canonical

Activated by TP53 loss in breast cancer

[3]

Wnt7a

Canonical/noncanonical

Activated by TP53 loss in breast cancer;

Secreted exclusively by aggressive breast cancer cells

[3, 44, 45]

Wnt7b

Canonical/noncanonical

Activated by TGFβ in breast cancer cells

[27, 45, 46]

Wnt8a

Noncanonical

–

[47]

Wnt8b

Canonical

–

[48]

Wnt9a

Canonical

Amplified in breast cancer

[16, 49]

Wnt9b

Canonical/noncanonical

–

[50,51,52]

Wnt10a

Canonical

Expressed in mouse ALDH-negative breast cancer cells in a time-dependent manner

[53]

Wnt10b

Canonical

Highly expressed in TNBC

[9, 54,55,56]

Wnt11

Canonical/noncanonical

Induced by ERα and β-Catenin

[57, 58]

Wnt16

Canonical/noncanonical

–

[59,60,61,62]

Porcupine

Canonical/noncanonical

–

[63]

p24 proteins

Canonical/noncanonical

TMED2 is increased in breast cancer

[64]

GPR177

Canonical/noncanonical

Markedly increased in breast cancer

[65]

Notum

Canonical/noncanonical

–

–

Norrin

Canonical/noncanonical

Significantly decreased in breast cancer

[66]

R-spondin

Canonical/noncanonical

R-spondin-1 is secreted by differentiated mammary luminal cells

[67, 68]

Cerberus

Canonical/noncanonical

–

–

sFRPs

Canonical/noncanonical

sFRP1, sFRP2, and sFRP5 are aberrantly methylated or epigenetically suppressed in breast cancer

[69,70,71,72,73,74]

WIF

Canonical/noncanonical

WIF-1 is epigenetically silenced or lost in breast cancer

[75, 76]

SOST

Canonical

Induced expression by Runx2/CBFβ in metastatic breast cancer cells

[77]

Dkks

Canonical/noncanonical

Dkk1 is epigenetically inactivated in breast cancer

[69]

IGFBP4

Canonical

Protease-resistant IGFBP4 is expressed in murine breast cancer

[78]