HOXA9 and non-small cell lung carcinoma: utilized the QDs-based FRET nanosensor technology to detect the tumor suppressor genes—protocadherin gamma subfamily B, 6 (PCDHGB6), Homeobox A9 (HOXA9) and Ras association domain family 1 isoform A (RASSF1A)-promoters methylation in non-small-cell lung carcinoma (NSCLC) early-stage specimens or noninvasive bronchial brushing tissues.