“…Out of these 20 studies, nine records utilized high-throughput assays of RNA sequencing [ 13 , 45 , 47 – 49 , 51 , 53 – 55 ], seven used qRT-PCR [ 24 – 26 , 43 , 46 , 50 , 52 ], three used Microarray analysis [ 27 , 41 , 44 ], and one used ISH [ 42 ] for quantification of piRNAs in patients biological specimen. The majority of these studies were conducted in China (nine studies) [ 13 , 24 , 25 , 27 , 41 – 43 , 46 , 55 ], three studies followed by the USA [ 48 , 49 , 53 ], three in Canada [ 47 , 51 , 54 ], two in Czech Republic [ 26 , 45 ], two in Germany [ 44 , 50 ], and one in Spain [ 52 ].…”