Genetic Determinants of Lung Cancer Prognosis in Never Smokers: A Pooled Analysis in the International Lung Cancer Consortium

Ancestry: How researchers use it and what they mean by it

Background: Ancestry is often viewed as a more objective and less objectionable population descriptor than race or ethnicity. Perhaps reflecting this, usage of the term "ancestry" is rapidly growing in genetics research, with ancestry groups referenced in many situations. The appropriate usage of population descriptors in genetics research is an ongoing source of debate. Sound normative guidance should rest on an empirical understanding of current usage; in the case of ancestry, questions about how researchers use the concept, and what they mean by it, remain unanswered. Methods: Systematic literature analysis of 205 articles at least tangentially related to human health from diverse disciplines that use the concept of ancestry, and semi-structured interviews with 44 lead authors of some of those articles. Results: Ancestry is relied on to structure research questions and key methodological approaches. Yet researchers struggle to define it, and/or offer diverse definitions. For some ancestry is a genetic concept, but for many-including geneticists-ancestry is only tangentially related to genetics. For some interviewees, ancestry is explicitly equated to ethnicity; for others it is explicitly distanced from it. Ancestry is operationalized using multiple data types (including genetic variation and self-reported identities), though for a large fraction of articles (26%) it is impossible to tell which data types were used. Across the literature and interviews there is no consistent understanding of how ancestry relates to genetic concepts (including genetic ancestry and population structure), nor how these genetic concepts relate to each other. Beyond this conceptual confusion, practices related to summarizing patterns of genetic variation often rest on uninterrogated conventions. Continental labels are by far the most common type of label applied to ancestry groups. We observed many instances of slippage between reference to ancestry groups and racial groups. Conclusion: Ancestry is in practice a highly ambiguous concept, and far from an objective counterpart to race or ethnicity. It is not uniquely a "biological" construct, and it does not represent a "safe haven" for researchers seeking to avoid evoking race or ethnicity in their work. Distinguishing genetic ancestry from ancestry more broadly will be a necessary part of providing conceptual clarity.

Modeling Costs and Life-Years Gained by Population-Wide Next-Generation Sequencing or Single-Gene Testing in Nonsquamous Non-Small-Cell Lung Cancer in the United States

PURPOSE

Many patients with actionable driver oncogenes (ADOs) are never identified and thus never receive targeted treatment. This study evaluated the economic impact and the potential life-years gained (LYG) that can be attributed to the extent of next-generation sequencing (NGS) testing in the United States compared with single-gene testing (SGT) in patients with metastatic nonsquamous non-small-cell lung cancer in the United States.

METHODS

A model was developed to evaluate incremental rates of SGT or NSG testing on the basis of LYG and cost per LYG. ADOs included for NGS included EGFR, ALK, ROS1, BRAF, RET, MET, and NTRK. SGT included EGFR and ALK. Assumptions were made for expected incidence of ADOs. Survival distributions were fit to published trial averages of median and 5-year overall survival. Treatment costs were estimated from drug cost averages. Reimbursement costs were based on data from the Center for Medicare and Medicaid Services.

RESULTS

Each incremental 10% increase in NGS testing produces an average of 2,627.4 additional LYG, with an average cost savings per LYG of $75 US dollars (USD). Replacing SGT at the current rate of 80% with NGS testing would result in an average additional 21,09.6 LYG and reduce cost per LYG by an average of $599 USD. If 100% of eligible patients were tested with NGS and each identified patient had matched treatment, the total average cost per LYG would be $16,641.57 USD.

CONCLUSION

On the basis of current evidence, population-level simulations demonstrate that clinically relevant gains in survival with non-negligible reduction in costs are obtainable from widespread adoption of NGS testing and appropriate treatment matching for patients with advanced nonsquamous non-small-cell lung cancer.

Short- and long-term survival outcomes among never smokers who developed lung cancer

BACKGROUND

Lung cancer is the leading cause of cancer death in the US. While an extensive literature exists detailing lung cancer risk factors and mortality among patients with a history of tobacco use, the data are more limited among individuals who have never smoked. The purpose of this investigation is to compare survival rates between the two groups and evaluate potential risk factors among never smokers.

METHODS

This retrospective study included 3380 smokers and 334 never smokers who were diagnosed with lung cancer at Stony Brook University Hospital between 2003 and 2016. 1-, 3-, 5- and 10-year survival outcomes, stratified by smoking status, were compared and Kaplan-Meier curves for overall survival are provided. Cox Proportional Hazard models were used to evaluate factors influencing survival among never smokers.

RESULTS

Never smokers with lung cancer were more likely to be female, be diagnosed with adenocarcinoma histology, and had fewer comorbidities than lung cancer patients who smoked. Although 60% of patients were diagnosed at a later stage of disease development, regardless of smoking status, overall short- and long-term survival was significantly higher among never smokers compared to those with a history of tobacco use. In addition to age and stage at diagnosis, a history of diabetes was found to be a significant prognostic factor for decreased survival among never smokers (HR=3.15, 95% CI (1.74, 5.71)).

CONCLUSIONS

Data from the present investigation suggest that, regardless of smoking status, approximately three of every five lung cancer patients are diagnosed at a later stage, and that both short- and long-term survival outcomes are significantly better among never smokers compared to those with a history of tobacco use. Additional studies are required to validate these findings and better explain the mechanistic drivers for the improved outcomes among never smokers.

The nonsmokers' and smokers' pathways in lung adenocarcinoma: Histological progression and molecular bases

There could be two carcinogenetic pathways for lung adenocarcinoma (LADC): the nonsmokers' pathway and the smokers' pathway. This review article describes the two pathways with special reference to potential relationships between histological subtypes, malignant grades, and driver mutations. The lung is composed of two different tissue units, the terminal respiratory unit (TRU) and the central airway compartment (CAC). In the nonsmokers' pathway, LADCs develop from the TRU, and their histological appearances change from lepidic to micropapillary during the progression process. In the smokers' pathway, LADCs develop from either the TRU or the CAC, and their histological appearances vary among cases in the middle of the progression process, but they are likely converged to acinar/solid at the end. On a molecular genetic level, the nonsmokers' pathway is mostly driven by EGFR mutations, whereas in the smokers' pathway, approximately one-quarter of LADCs have KRAS mutations, but the other three-quarters have no known driver mutations. p53 mutations are an important factor triggering the progression of both pathways, with unique molecular alterations associated with each, such as MUC21 expression and chromosome 12p13-21 amplification in the nonsmokers' pathway, and HNF4α expression and TTF1 mutations in the smokers' pathway. However, investigation into the relationship between histological progression and genetic alterations is in its infancy. Tight cooperation between traditional histopathological examinations and recent molecular genetics can provide valuable insight to better understand the nature of LADCs.

[Mechanism of DERL3 Affecting the Proliferation, Invasion and Metastasis of Lung Adenocarcinoma A549 Cells]

BACKGROUND

Derlin 3 (DERL3) is downregulated in colorectal cancer (CRC) samples. Its level is closely linked to lymphatic metastasis or distant metastasis rate in CRC patients. However, its biological behavior in lung adenocarcinoma were rarely reported. The aim of this study is to investigate the ectopic expression of DERL3 in lung adenocarcinoma tissues and its effect on the invasion and metastasis of lung adenocarcinoma A549 cell line to reveal the possible mechanism of invasion and metastasis of lung adenocarcinoma.

METHODS

Lung adenocarcinoma microarray gene chip data included 3 cases of lymph node metastasis and 3 cases of lung adenocarcinoma tissue without lymph node metastasis. The GEDS and Kaplan-Meier plot queries the survival curve and expression level of DERL3. Western blot was used to detect the expression of DERL3 in lung adenocarcinoma cells. The efficiency of knockdown DERL3 gene was detected by Western blot assay. Transwell detected the number of cells passing through the basement membrane of the transwell. EDU assay detected cell proliferation ability. Western blot detected the expression of epithelial-mesenchymal transition related proteins E-cadherin and Vimentin.

RESULTS

The microarray gene chip results showed that compared with lung adenocarcinoma tissues without lymph node metastasis, 1,314 mRNAs in lung adenocarcinoma tissues with lymph node metastasis were up-regulated, 400 mRNAs were down (P<0.05). The expression of DERL3 increased in lung adenocarcinoma (P<0.05). The results of survival curve showed that the lung cancer patients with high expression of DERL3 with poor prognosis (P<0.05). Western blot results indicated that plasmid transfection was successful. Knockdown of DERL3 suppressed the ability of proliferation, invasion and migration in A549 cells (P<0.05). After knockdown of DERL3, the expression level of Vimentin was decreased, while E-cadherin expression increased (P<0.05).

CONCLUSIONS

Knockdown of DERL3 inhibited the proliferation, invasion and metastasis of A549 cells.

Identification of a Ferroptosis-Related LncRNA Signature as a Novel Prognosis Model for Lung Adenocarcinoma

Lung adenocarcinoma (LUAD) is a highly heterogeneous malignancy, which makes prognosis prediction of LUAD very challenging. Ferroptosis is an iron-dependent cell death mechanism that is important in the survival of tumor cells. Long non-coding RNAs (lncRNAs) are considered to be key regulators of LUAD development and are involved in ferroptosis of tumor cells, and ferroptosis-related lncRNAs have gradually emerged as new targets for LUAD treatment and prognosis. It is essential to determine the prognostic value of ferroptosis-related lncRNAs in LUAD. In this study, we obtained RNA sequencing (RNA-seq) data and corresponding clinical information of LUAD patients from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) database and ferroptosis-related lncRNAs by co-expression analysis. The best predictors associated with LUAD prognosis, including C5orf64, LINC01800, LINC00968, LINC01352, PGM5-AS1, LINC02097, DEPDC1-AS1, WWC2-AS2, SATB2-AS1, LINC00628, LINC01537, LMO7DN, were identified by Least Absolute Shrinkage and Selection Operator (LASSO) Cox regression analysis, and the LUAD risk prediction model was successfully constructed. Kaplan-Meier analysis, receiver operating characteristic (ROC) time curve analysis and univariate and multivariate Cox regression analysis and further demonstrated that the model has excellent robustness and predictive ability. Further, based on the risk prediction model, functional enrichment analysis revealed that 12 prognostic indicators involved a variety of cellular functions and signaling pathways, and the immune status was different in the high-risk and low-risk groups. In conclusion, a risk model of 12 ferroptosis related lncRNAs has important prognostic value for LUAD and may be ferroptosis-related therapeutic targets in the clinic.

Long noncoding RNA LMO7DN inhibits cell proliferation by regulating the cell cycle in lung adenocarcinoma

In our previous study, we reported that the long noncoding RNA, LMO7 downstream neighbor (LMO7DN), has a strong prognostic value in lung adenocarcinoma (LUAD). In this study, we further investigated the role of LMO7DN in LUAD progression. LMO7DN was found to be expressed at low levels in LUAD tissues, and its high expression predicted good prognosis. Bioinformatics analysis indicated that LMO7DN was closely associated with the cell cycle. Furthermore, we found that cell proliferation was significantly enhanced following knockdown of LMO7DN, and the number of cells in the G2/M phase was markedly decreased, whereas there was no change in apoptosis. Thus, LMO7DN inhibits cell proliferation by affecting the cell cycle and is of significant prognostic value in LUAD.