Non-small cell lung cancer: epidemiology, risk factors, treatment, and survivorship

Evaluation of glutathione metabolic genes on outcomes in advanced non-small cell lung cancer patients after initial treatment with platinum-based chemotherapy: an NCCTG-97-24-51 based study

INTRODUCTION

We evaluated the role of glutathione-related genotypes on overall survival, time to progression, adverse events, and quality of life (QOL) in stage IIIB/IV non-small cell lung cancer patients who were stable or responding from initial treatment with platinum-based chemotherapy and subsequently randomized to receive daily oral carboxyaminoimidazole or a placebo.

METHODS

Of the 186 total patients, 113 had initial treatment with platinum therapy and DNA samples of whom 46 also had QOL data. These samples were analyzed using six polymorphic DNA markers that encode five important enzymes in the glutathione metabolic pathway. Patient QOL was assessed using the Functional Assessment of Cancer Therapy-Lung and the UNISCALE QOL questionnaires. A clinically significant decline in QOL was defined as a 10% decrease from baseline to week-8. Multivariate analyses were used to evaluate the association of the genotypes on the four endpoints.

RESULTS

Patients carrying a GCLC 77 genotype had a worse overall survival (hazard ratio (HR) = 1.5, p = 0.05). Patients carrying the GPX1-CC genotype had a clinically significant decline in the UNISCALE (odds ratio (OR): 7.5; p = 0.04), total Functional Assessment of Cancer Therapy-Lung score (OR: 11.0; p = 0.04), physical (OR: 7.1; p = 0.03), functional (OR: 5.2; p = 0.04), and emotional well-being constructs (OR: 23.8; p = 0.01).

CONCLUSIONS

Genotypes of glutathione-related enzymes, especially GCLC, may be used as host factors in predicting patients' survival after platinum-based chemotherapy. GPX1 may be an inherited factor in predicting patients' QOL. Further investigation to define and measure the effects of these genes in chemotherapeutic regimens, drug toxicities, disease progression, and QOL are critical.

RASSF1A, APC, ESR1, ABCB1 and HOXC9, but not p16INK4A, DAPK1, PTEN and MT1G genes were frequently methylated in the stage I non-small cell lung cancer in China

PURPOSE

To identify the DNA methylation biomarkers for the detection of the stage I non-small cell lung cancer (NSCLC).

MATERIALS AND METHODS

The methylated state of p16INK4A, ESR1, HOX9, RASSF1A, DAPK1, PTEN, ABCB1, MGMT, APC and MT1G genes that have been reported frequently methylated in lung cancer was determined using methylation-specific PCR in four lung cancer cell lines, 124 cancer tissues of the stage I NSCLC and 26 non-cancerous disease tissues.

RESULT

The RASSF1A (53/124, 42.74%), APC (49/123, 39.52%), ESR1 (37/124, 29.84%), ABCB1 (31/124, 24.19%, MT1G (25/124, 20.16%) and HOXC9 (17/124, 13.71%) genes were more frequently methylated in the lung tissue from the stage I NSCLC than the non-cancerous lesion patients (2/26, 7.69%, P < 0.01; 2/26, 7.69%, P < 0.01; 2/26, 7.69%, P < 0.05; 1/26, 3.85% P < 0.01; 0/26 0%, P value: <0.01; 0/26, 0%, P < 0.05, respectively). p16INK4A was methylated in 28/124 (22.56%) of cancer tissues and 2/26 (7.69%) of non-cancerous tissues (P value >0.05). No significant association between the methylated state of the genes and the smoking, age or the pathologic types (squamous carcinoma, adenoma and the mixed types) was found. However, p16INK4A methylation was more frequently detected in the male (23/80, 28.75%) than the female (5/44, 11.36%, P > 0.05) patients. MGMT was barely methylated: 1/67, 1.49%), while DAPK1 and PTEN were not at all methylated in the cancer groups.

CONCLUSIONS

Methylation analysis in tissue of RASSF1A, APC, ESR1, ABCB1 and HOXC9 genes confirmed 79.8% of the existing diagnosis for the stage I NSCLC at specificity: 73.1%. The insufficiency of predicting disease onset in China, using the previously recommended targets (MGMT, DAPK1 and PTEN) in the United States reflects a potential disease disparity between these two populations. Alternatively, methylated state of this set of genes may be more specific to the late rather than the early stage of NSCLC.

Protons make tumor cells move like clockwork

Cancer accounts for 13% of the yearly total mortality worldwide. Most cancer deaths are the sequel of metastatic diseases rather than of primary tumor growth. Thus, the major challenge in tumor therapy is the tumor cells' ability to metastasize. The extent to which a tumor metastasizes correlates with the tumor cells' migratory activity. Tumor cell migration requires a coordinated formation and release of cell adhesion contacts, a controlled cytoskeletal dynamics, the digestion and reorganization of the extracellular matrix, and local ion and water transport across the plasma membrane. All of these operations depend on intracellular pH (pH(i)) and extracellular pH (pH(e)). Numerous H(+), HCO (3) (-) , and monocarboxylate transporters as well as different carbonic anhydrase isozymes have considerable impact on pH(i) and pH(e) which spotlights them as possible, potential targets for anticancer therapeutics. Especially in solid tumors whose vascularization is often not sufficient, tumor cells cope with hypoxia and the resulting glycolysis by overexpressing the Na(+)/H(+) exchanger NHE1, monocarboxylate transporters MCT1 and/or MCT4, and the carbonic anhydrase CA IX. NHE1, MCT, and CA IX activity lead to an acidification of the extracellular space in order to maintain the cytosolic pH homeostasis stable. The present article gives a review on how this characteristic, acidic tumor micro- and nanoenvironment controls tumor cell migration.

DNA methylation-based biomarkers for early detection of non-small cell lung cancer: an update

Lung cancer is the number one cancer killer in the United States. This disease is clinically divided into two sub-types, small cell lung cancer, (10–15% of lung cancer cases), and non-small cell lung cancer (NSCLC; 85–90% of cases). Early detection of NSCLC, which is the more common and less aggressive of the two sub-types, has the highest potential for saving lives. As yet, no routine screening method that enables early detection exists, and this is a key factor in the high mortality rate of this disease. Imaging and cytology-based screening strategies have been employed for early detection, and while some are sensitive, none have been demonstrated to reduce lung cancer mortality. However, mortality might be reduced by developing specific molecular markers that can complement imaging techniques. DNA methylation has emerged as a highly promising biomarker and is being actively studied in multiple cancers. The analysis of DNA methylation-based biomarkers is rapidly advancing, and a large number of potential biomarkers have been identified. Here we present a detailed review of the literature, focusing on DNA methylation-based markers developed using primary NSCLC tissue. Viable markers for clinical diagnosis must be detectable in 'remote media' such as blood, sputum, bronchoalveolar lavage, or even exhaled breath condensate. We discuss progress on their detection in such media and the sensitivity and specificity of the molecular marker panels identified to date. Lastly, we look to future advancements that will be made possible with the interrogation of the epigenome.

Reliability and accuracy of interview data in non-smoking female lung cancer case-control study

Background

Valid interview data is critical to the final results of the study. The purpose of this study was to investigate the reliability of epidemiological data obtained in non-smoking female lung cancer case-control study in China.

Methods

Fifty-six pairs of cases and controls, 10% percent of all the collected subjects were re-interviewed by three interviewers who underwent identical standardized training. A limited number of questions included in the original survey were asked again, the responses from the re-interview were compared with the original interview. Kappa was calculated by negative rates of agreement, positive rates of agreement and total rates of agreement to the accordance degree between the two interviews.

Results

The Kappa values were all more than 0.5 in all the studied indexes. The Kappa values descended from 0.92 in family history of cancer to 0.56 in oral contraception use. Errors in collecting and classifying data did occur, and were especially common for complicated clinical events, such as a drug exposure occurring many years before.

Conclusion

We identified four sources of this variability, three in collecting the data, and one in coding. As a result of these findings, strategies are proposed for improving the quality of interview data obtained in epidemiological research. Before finding a good solution, the strategy of data collecting and coding should be simple and easy to inspect.