Early detection of gallbladder cancer: Current status and future perspectives

Table 10 Liquid biopsy in the diagnosis of gall bladder cancer

Liquid biopsy	Detection method	Sensitivity and specificity	Implementation barrier in early diagnosis	Ref.
CTC	Flow cytometric detection, nano microfluid chip, immunoaffinity (EpCAM), microfiltration (ISET)	55.6%, 100.0%	Very low detection rate in early stage	[193]
			CTCs in peripheral blood (approximately 1 CTC per 106-10 Leukocytes)
			Large blood volume required to detect CTC
			Short half-life of CTC makes it difficult to analyse
miRNAs	qRT-PCR, microarrays, NGS	80%-90%, 80%-90%	miRNA expression can vary depending on samples	[198,199]
			Delay in processing, and temperature fluctuations can alter miRNA levels
			Low abudance, platform dependency, lack of standardization, high cost
LncRNA	qRT-PCR, microarrays, NGS	84%-100%	Low abundance, delay in processing, and temperature fluctuations can alter miRNA levels	[198,199]
			Platform dependency, lack of standardization, high cost
ctDNA/cfDNA	qPCR, dPCR, ddPCR, NGS, high-throughput quantitative methylation assays	78%-100%, 80%-100%	Separation of ctDNA from the cfDNA (mixture of non-mutant tumor DNA, normal DNA and tumor DNA) is technically challenging	[200,201]
	RBBS		High false negative rate because of tumor heterogenicity
			ctDNA used for genetic testing only 0.01% of tumor
			Limited representation of tumor environment
			No standardization and no universally accepted cutoff for detection
			High cost
			Low availability
Bile as liquid biopsy	qRT-PCR, microarrays, NGS	45.8% and 99.9%	Invasive methods to aspirate bile from GB	[202]
			No standardized methods and cutoff value

ctDNA: Circulating tumor DNA; cfDNA: Cell-free DNA; miRNAs: MicroRNAs; lncRNAs: Long noncoding RNAs; GB: Gall bladder; dPCR: Digital polymerase chain reaction; ddPCR: Digital droplet polymerase chain reaction; NGS: Next-generation sequencing; RBBS: Reduced representation bisulfite sequencing; qRT-PCR: Quantitative real-time reverse transcription polymerase chain reaction; CTC: Circulating tumor cell.