Global gene expression landscape of gallbladder cancer and advances in targeted therapeutic strategies

Table 1 Summarization of most significant dysregulated genes in the genesis of GBC and their geographic heterogeneity

Category of gene	Gene name	Criteria of genetic dysregulation	Geographic heterogeneity in proportion of dysregulated expression amongst studied GBC samples
Oncogenes	EGFR	Overexpression	8.1% in Japan - 93.3% in North India
	ERBB2	Overexpression	12.8% in Chile - 56.6% in North India
	CCND1 (encoding cyclin D1)	Overexpression	5.6% in South Korea - 68.3% in China
	BCL2	Overexpression	7.7% in South Korea - 18.4% in Japan
	BRIC5 (encoding survivin)	Overexpression	58% in India - 76.5% in Turkey
	MYC	Amplification	3.7% in Japan - 86.7% in Brazil
	MET	Overexpression	5.6% in Japan - 74% in South Korea
Tumor supressor genes	FHIT	Downregulation	45% in Japan - 94% in Chile
	CDKN2A	Downregulation	20% in South Korea - 88% in North India
	Mutated TP53	Overexpression	56% in North India - 71% in Spain
Angiogenesis factors	PTGS2 (encoding COX-2)	Overexpression	59% in Slovenia - 80% in South Korea
	VEGFA	Overexpression	48% in India - 81% in Chile
Cell-adhesion molecule	CDH1 (encoding E-cadherins)	Downregulation	26% in Chile - 67% in North India
Cancer stem cell gene	POU5F1 (encoding Oct4)	Overexpression	59% in China - 64.5% in North India
Immunoinhibitory molecule	CD274 (encoding PD-L1)	Overexpression	10.9% in Croatia - 40% in Japan

GBC: Gallbladder cancer.