Cytogenetic and FISH Examination of 3p Abnormalities in Lung Cancer Patients

Objective: Deletions or loss of heterozygosity in chromosome 3p are very common in small-cell lung cancer (SCLC) and lung adenocarcinoma (ADC) cases. These are typically found in tumor cells but rarely observed in lymphocytes. This study aimed to evaluate the frequency of 3p deletions and/or abnormalities in the blood of lung cancer patients using conventional cytogenetics and fluorescence in situ hybridization (FISH), by targeting the fragile histidine triad diadenosine triphosphatase (FHIT) gene located at the commonly deleted region of 3p14.2, in lung cancers. Materials and Methods: The study examined 24 SCLC patients, 30 ADC patients, and 20 healthy controls. It used standard procedures to perform a 72-h lymphocyte culture, G-banding, and FISH. Results: All patient group cases showed multiple numerical and structural abnormalities, with numerical abnormalities being more prominent and involving all chromosomes. The following two 3p abnormalities were detected in one patient: del(3)(p22) and t(3;5) (p25;q31). FISH showed positive results regarding FHIT deletion in 9 (30%) ADC, and 7 (29%) SCLC patients. Conclusion: Regardless of the rarity of 3p abnormalities in lymphocytes, a high frequency of chromosomal aberrations may indicate genomic instability. Nevertheless, due to being a time-consuming and expertise-requiring technique, conventional cytogenetics is not recommended for lung cancer monitoring. However, the FISH results suggested that using FISH to examine FHIT gene status in lymphocytes could be a promising biomarker for lung cancer.