“…Oral brushing samples are then spun down onto slides and stained using the Feulgen-thionin reaction [ 105 , 106 , 107 ]. Brush biopsies are subsequently stained using PAP staining [ 28 , 36 , 39 , 43 , 104 , 107 , 108 , 109 , 110 , 111 , 112 , 113 , 114 , 115 , 116 , 117 , 118 , 119 , 120 , 121 , 122 ] or argyrophilic nucleolar organizer region (AgNOR) [ 32 , 107 , 118 , 121 ] for conventional cytology (CC) and liquid-based cytology (LBC). For molecular analysis, mass spectrometry [ 123 , 124 ] and DNA-image cytometry (DNA-ICM) [ 42 , 125 , 126 , 127 , 128 , 129 ] are utilized.…”