Table 3.

Snail1 expression in cancers (listed in alphabetical order)

Type of Cancer	Snail Expression	Change in expression over disease progression	Prognostic significance	Reference(s)
Bladder carcinoma	Inverse correlation with E-cadherin [130]; low expression level (only 16% of carcinoma tissues, n = 120)—Slug and Twist appear to be more important [140]	Increased expression in node-positive vs. node-negative tumors; 3 year progression free survival rate with positive Snail expression only 15% [140]	Snail expression associated with tumor recurrence; elevated expression is significant, independent prognostic factor [140],[141]	[130],[140],[141]
Breast carcinoma	None in normal breast epithelium; in 47% of IDCs (n = 17); none in ILCs (n = 4); expression correlates with lymph node metastases; not found in cells with constitutively inactive E-cadherin; expression opposes E-cadherin [128]; Snail overexpressed; Snail/E-cadherin ratio significantly higher [129]	Snail expression in IDCs (n = 17): grade 1—none; grade 2—more than half; grade 3—most [128]	Potential marker of IDC malignancy [128]; High expression correlated with shorter effusion-free, disease-free, and overall survival; correlated with lymph node metastases and high histologic grade (n = 16) [129]	[128],[129]
Cervical carcinoma	Snail expressed in 94% of samples (n = 70) and ZEB-1 in 96%; nuclear expression of both correlates with advanced FIGO stage and lymph node metastasis; expression of Snail correlates with poor differentiation [153]	High Snail expression associated with late FIGO stage, lymph node metastasis, and poor differentiation [153]		[153]
Colorectal carcinoma	Inverse correlation with E-cadherin [130]; markedly high expression (78% of tested tumors, n = 59) of Snail; Snail-positive in older age group than Snail-negative (mean 58.9 vs. 49.8, n = 59) [138]; Snail expressed in all tested CRC cell lines (Western blot); expression increased migration and invasiveness; decreased E-cadherin; led to CSC-like phenotype and spindle morphology [139]	Increase in expression over disease progression: 15/23 stage III vs. 6/6 stage IV [138]; significantly higher rate of metastasis among Snail-expressing than Snail-negative [139]	Snail expression indicates high risk of distant metastases [138],[139]	[130],[138],[139]
Gastric carcinoma	Snail expression higher in diffuse than intestinal type [134]; inverse correlation with E-cadherin; significantly reduced E-cadherin expression; Snail expression more comparable to breast than ovarian carcinoma [129]	Overexpression associated with tumor size, depth of invasion, lymph node metastasis, shortened survival [135]	Considered independent predictor of poor prognosis [135]	[129],[134],[135]
Hepatocellular carcinoma	Inverse correlation of mRNA and protein levels with E-cadherin (E-cadherin in Hep-G2 while Snail in HuL-1, Changliver, HLE, and HLF cells) [130]; Snail correlates with invasiveness and metastasis, Snail overexpression in 23% of cases (n = 47) [131]	Higher Snail expression in higher grade cases (n = 12) [132]	Risk factor for early recurrence (n = 47) [131]; Snail correlated with portal vein invasion, metastasis, poorer prognosis in recurrence-free survival [132]	[130]–[132]
Melanomas	High mRNA expression in all tested melanoma cell lines but not primary melanocytes; low E-cadherin in presence of Snail [142]; inverse correlation with E-cadherin [130]; Snail confers invasive and immunosuppressive properties [143]			[130],[142],[143]
Oral squamous carcinoma	Low E-cadherin/high Snail expression cells more invasive; E-cadherin positive had cuboidal shape and E-cadherin negative cells were spindle-shaped; inverse correlation with E-cadherin [136]			[136]
Ovarian carcinoma	Less expressed than in breast carcinoma [129]; lower expression in effusions than primary tumors and solid metastases; mRNA levels not statistically different among the three; complete cytoplasmic localization in effusions [133]		High E-cadherin expression correlated with disease-free survival; MMP-2 is considered a marker of poor prognosis; Snail associated with distant metastases [129]	[129],[133]
Pancreatic carcinoma	Inverse correlation with E-cadherin [130]; significantly reduced E-cadherin expression [129]; 78% of tested tissues (n = 36, ductal adenocarcinoma) showed Snail expression; Snail higher in undifferentiated cell lines (MiaPaCa-2 and Panc-1) than differentiated (Capan-1, HPAF-2, AsPC-1) [137]			[129],[130],[137]
Prostate cancer	Significant loss of E-cadherin and syndecan 1 in high grades, along with high Snail; only nuclear localization in PC3 cell lines [151]	High Snail expression correlates with high Gleason grade, increased malignancy [151]		[151]
Synovial sarcoma	Snail mRNA found in all cases tested (n = 20), but E-cadherin mutations appear to be more important than Snail expression [144]			[144]