Evaluating circulating cell-free DNA and DNA integrity index as biomarkers in non-small cell lung cancer.

BACKGROUND: Analysis of free DNA molecules shed from tumour cells in plasma of patients referred as circulating tumour DNA (ctDNA) with reference to physiological circulating cell-free DNA (cfDNA) is nowadays exploited as liquid biopsy and is considered a new emerging promising biomarker for diagnosis, selection of proper treatment, and prognosis of cancer. DNA integrity index (DII) is assessed by calculating the ratio between the concentration of long cfDNA strands released from tumour cells (ALU247) and the short strands released from normal cells (ALU115). The aim of the current study was to evaluate DII as a potential diagnostic and prognostic biomarker of NSCLC. METHODS: Our study included 48 NSCLC patients diagnosed as primary NSCLC before starting treatment, 30 COPD patients diagnosed clinically, radiologically, and subjected to chest high-resolution computerized tomography, and 40 healthy controls. cfDNA concentration and DII were measured by quantitative real-time polymerase chain reaction (qPCR). RESULTS: ALU115, ALU247, and DII were significantly higher in NSCLC compared to COPD patients (p < 0.0001) and controls (p < 0.0001) and in COPD patients compared to control subjects (p < 0.0001). DII positively correlated with the stage of tumour (p = 0.01), tumour metastasis (p = 0.004), and with adenocarcinoma compared to other histopathological types (p = 0.02). To evaluate clinical utility of DII in NSCLC, ROC curve analysis demonstrated an AUC of 0.91 at a cut-off value of 0.44 with total accuracy = 85.6%, sensitivity = 90%, specificity = 83%, PPV = 78.1%, and NPV = 92.1%. CONCLUSION: cfDNA and DII represent a promising diagnostic and prognostic tool in NSCLC. This type of noninvasive liquid biopsy revealed its chance in the screening, early diagnosis, and monitoring of NSCLC.

Study of genetic variants in chromosome 5p15.33 region in non-smoker lung cancer patients.

INTRODUCTION: Genome-wide association studies have identified that genetic polymorphisms in the telomerase reverse transcrip-tase (TERT) and cleft lip and palate transmembrane 1-like (CLPTM1L) genes may play important roles in the development of lung cancer in never smokers. MATERIAL AND METHODS: This study was aiming to evaluate the associations between the risk of lung cancer in never smokers and single nucleotide polymorphisms in these genes by Real-Time Taqman assay, in forty lung cancer patients and forty apparently healthy age-matched controls selected from the chest department, Kasr Al-Ainy hospital from June 2018 to January 2019. RESULTS: Adenocarcinoma was the most common histopathological subtype of lung cancer in the study patients. Also, the prevalence of females having adenocarcinoma was more common than males. The heterozygous form of the CLPTM1L occurred more frequently in the subjects aged above 46 years (P=0.019). There was a significant association between (rs 2730100) (c. 1574-3777C>A) TERT and CLPTM1L (rs 451360) (c.1532+ 1051C>A) genotypes and the incidence of lung cancer in never smokers, especially adenocarcinoma, a subtype of non-small cell lung carcinoma (NSCLC). CONCLUSIONS: Polymorphism in the telomerase reverse transcriptase (TERT) and cleft lip and palate transmembrane 1 like (CLPT-M1L) genes may play an important role in the development of NSCLC, especially adenocarcinoma subtype. The two genes are located in the chromosome 5p15.33.