Mutational Landscape of DDR2 Gene in Lung Squamous Cell Carcinoma Using Next-generation Sequencing

Landscape of targeted therapies for lung squamous cell carcinoma

Lung cancer, a common type of malignant neoplasm, has seen significant advancements in the treatment of lung adenocarcinoma (LUAD). However, the management of lung squamous cell carcinoma (LSCC) continues to pose challenges. Traditional treatment methods for LSCC encompass surgical resection, chemotherapy, and radiotherapy. The introduction of targeted therapy and immunotherapy has greatly benefited LSCC patients, but issues such as limited immune response rates and adverse reactions persist. Therefore, gaining a deeper comprehension of the underlying mechanisms holds immense importance. This review provides an in-depth overview of classical signaling pathways and therapeutic targets, including the PI3K signaling pathway, CDK4/6 pathway, FGFR1 pathway and EGFR pathway. Additionally, we delve into alternative signaling pathways and potential targets that could offer new therapeutic avenues for LSCC. Lastly, we summarize the latest advancements in targeted therapy combined with immune checkpoint blockade (ICB) therapy for LSCC and discuss the prospects and challenges in this field.

Squamous cell lung cancer: Current landscape and future therapeutic options

Squamous cell lung cancers (lung squamous cell carcinomas [LUSCs]) are associated with high mortality and a lack of therapies specific to this disease. Although recurrent molecular aberrations are present in LUSCs, efforts to develop targeted therapies against receptor tyrosine kinases, signaling transduction, and cell cycle checkpoints in LUSCs were met with significant challenges. The present therapeutic landscape focuses on epigenetic therapies to modulate the expression of lineage-dependent survival pathways and undruggable oncogenes. Another important therapeutic approach is to exploit metabolic vulnerabilities unique to LUSCs. These novel therapies may synergize with immune checkpoint inhibitors in the right therapeutic context. For example, the recognition that alterations in KEAP1-NFE2L2 in LUSCs affected antitumor immune responses created unique opportunities for targeted, metabolic, and immune combinations. This article provides a perspective on how lessons learned from the past influence the current therapeutic landscape and opportunities for future drug development for LUSCs.

Special issue "The advance of solid tumor research in China": Discoidin domain receptor 2 promotes colorectal cancer metastasis by regulating epithelial mesenchymal transition via activating AKT signaling

Tumor metastasis is one of the main reasons for the high mortality rate associated with colorectal cancer (CRC). However, its underlying mechanisms have not been fully understood. Here, we reported that the expression of discoidin domain receptor 2 (DDR2) was significantly upregulated in CRC tissues compared with that in normal adjacent tissues. The expression level of DDR2 was negatively associated with prognosis of CRC patients. Therefore, DDR2 may play an oncogenic role in CRC development. Furthermore, DDR2 induced epithelial mesenchymal transition in CRC cells and regulated their invasive and metastatic capacity in vitro and in vivo. Mechanistically, increased DDR2 expression level activated the AKT/GSK-3β/Slug signaling pathway. In conclusion, these findings showed that DDR2 promoted CRC metastasis and DDR2 inhibition might represent an effective therapeutic strategy for local advanced and metastatic CRC treatment. This article is protected by copyright. All rights reserved.

Discoidin Domain Receptor 2: A New Target in Cancer

BACKGROUND

Discoidin domain receptor is a new and unique type of receptor tyrosine kinases, which binds to collagen, the main compose of an extracellular matrix. DDR1 was identified to mediate cell aggregation, and dysregulation of DDR2 has also been shown to be involved in tumor pathogenesis, although its role in cancer development and progression remains controversial.

SUMMARY

Abnormal expression and mutations of DDR2 have been reported in several cancer types and its participation in different aspects of tumor progression, including proliferation, migration, invasion, metastasis, epithelial-mesenchymal transition, and chemotherapy resistance. Moreover, novel DDR2 inhibitors have been designed and indicate a therapeutic effect for the cancer treatment. Key Messages: In this review, we summarize the current knowledge on the role of DDR2 in cancer promotion and the potential therapeutic value of targeting DDR2.

Evaluation on the Distribution of EGFR, KRAS and BRAF Genes and the Expression of PD-L1 in Different Types of Lung Cancer

Objective

To evaluate the distribution of high frequency mutant genes and the expression of PDL1 in different types of lung cancer.

Methods

This retrospective analysis was conducted on 330 patients who were diagnosed with primary lung cancer and treated in our hospital from October 2018 to October 2020. The patients were listed into non-small cell carcinoma group (101 cases), squamous carcinoma group (28 cases) and adenocarcinoma group (201 cases) according to their pathological results. The gene mutations were detected using EGFR, KRAS, and BRAF gene mutation detection kits, and the expression of PDL1 was detected by immunostaining. The mutation of EGFR, KRAS and BRAF genes and PDL1 expression in patients with different types of lung cancer were compared.

Results

The patients in the adenocarcinoma group had the highest incidence of EGFR gene mutation, the mutation rate of the gene whose mutation location was exon 18 was significantly higher, and the difference between each group was statistically significant (P < 0.05). The patients in the adenocarcinoma group had the highest incidence of KRAS gene mutation, the mutation rate of the gene whose mutation location was exon 2 was obviously the highest, exon 15 was the lowest, and the difference between each group was statistically significant (P < 0.05). There was no significant difference in the distribution of BRAF gene mutations among groups, and all mutations occurred on exon 15, with no statistically significant difference between each group (P > 0.05). PD-L1 expression in NSCLC patients was significantly higher than that in other lung cancer patients (P < 0.05).

Conclusion

EGFR and KRAS genes showed obvious specific expressions in patients with different types of lung cancer and they were more common in patients with lung adenocarcinoma. Gene mutation and PDL1 expression are high in patients with lung adenocarcinoma.

Expression Profiling of Driver Genes in Female Never-smokers With Non-adenocarcinoma Non-small-cell Lung Cancer in China

BACKGROUND

Although smoking is a primary cause of lung cancer, females are overrepresented among never-smokers with the disease. The mutational landscape of adenocarcinoma in never-smoking females has been extensively profiled; however, there is little knowledge about genomic alterations in non-adenocarcinoma non-small-cell lung cancer (NA-NSCLC). In the study, we reviewed the status of oncogenic drivers of NA-NSCLC in these populations.

MATERIALS AND METHODS

Comprehensive genomic profiling was performed on DNA extracted from formalin-fixed, paraffin-embedded sections of 52 NA-NSCLC tissues, including 35 squamous cell carcinomas (SQCCs), 11 adenosquamous carcinomas, 5 pulmonary sarcomatoid carcinoma, and 1 large cell carcinoma by next-generation sequencing within a panel of 68 cancer-related genes.

RESULTS

Mutations of the common oncogenic drivers (EGFR, KRAS, ALK, ROS1, MET, RET, and ERBB2) occurred in 61.5% of cases. The frequency of well-established targets (EGFR and ALK), new targets without widely available therapies (MET and ERBB2), and potentially actionable targets (RET and DDR2) in SQCCs of female never-smokers was significantly higher than that in The Cancer Genome Atlas dataset. There were 31%, 82%, and 80% of cases with SQCC, adenosquamous carcinoma, and pulmonary sarcomatoid carcinoma, respectively, harboring at least one of the following targets: EGFR, ALK, ERBB2, and MET. Approximately 78% (7/9) of the patients responded to various targeted treatments.

CONCLUSION

Female never-smokers with NA-NSCLC in this study had a high frequency of currently known or potentially actionable oncogenic alterations and could benefit from targeted therapy. Our study also provides evidence for the recommendation of molecular analysis in never-smoking female SQCC.

Lung Cancers: Molecular Characterization, Clonal Heterogeneity and Evolution, and Cancer Stem Cells

Lung cancer causes the largest number of cancer-related deaths in the world. Most (85%) of lung cancers are classified as non-small-cell lung cancer (NSCLC) and small-cell lung cancer (15%) (SCLC). The 5-year survival rate for NSCLC patients remains very low (about 16% at 5 years). The two predominant NSCLC histological phenotypes are adenocarcinoma (ADC) and squamous cell carcinoma (LSQCC). ADCs display several recurrent genetic alterations, including: KRAS, BRAF and EGFR mutations; recurrent mutations and amplifications of several oncogenes, including ERBB2, MET, FGFR1 and FGFR2; fusion oncogenes involving ALK, ROS1, Neuregulin1 (NRG1) and RET. In LSQCC recurrent mutations of TP53, FGFR1, FGFR2, FGFR3, DDR2 and genes of the PI3K pathway have been detected, quantitative gene abnormalities of PTEN and CDKN2A. Developments in the characterization of lung cancer molecular abnormalities provided a strong rationale for new therapeutic options and for understanding the mechanisms of drug resistance. However, the complexity of lung cancer genomes is particularly high, as shown by deep-sequencing studies supporting the heterogeneity of lung tumors at cellular level, with sub-clones exhibiting different combinations of mutations. Molecular studies performed on lung tumors during treatment have shown the phenomenon of clonal evolution, thus supporting the occurrence of a temporal tumor heterogeneity.

Distribution of KRAS, DDR2, and TP53 gene mutations in lung cancer: An analysis of Iranian patients

Purpose

Lung cancer is the deadliest known cancer in the world, with the highest number of mutations in proto-oncogenes and tumor suppressor genes. Therefore, this study was conducted to determine the status of hotspot regions in DDR2 and KRAS genes for the first time, as well as in TP53 gene, in lung cancer patients within the Iranian population.

Experimental design

The mutations in exon 2 of KRAS, exon 18 of DDR2, and exons 5–6 of TP53 genes were screened in lung cancer samples, including non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC) using PCR and sequencing techniques.

Results

Analysis of the KRAS gene showed only a G12C variation in one large cell carcinoma (LCC) patient, whereas variants were not found in adenocarcinoma (ADC) and squamous cell carcinoma (SCC) cases. The Q808H variation in the DDR2 gene was detected in one SCC sample, while no variant was seen in the ADC and LCC subtypes. Variations in the TP53 gene were seen in all NSCLC subtypes, including six ADC (13.63%), seven SCC (15.9%) and two LCC (4.54%). Forty-eight variants were found in the TP53 gene. Of these, 15 variants were found in coding regions V147A, V157F, Q167Q, D186G, H193R, T211T, F212L and P222P, 33 variants in intronic regions rs1625895 (HGVS: c.672+62A>G), rs766856111 (HGVS: c.672+6G>A) and two new variants (c.560-12A>G and c.672+86T>C).

Conclusions

In conclusion, KRAS, DDR2, and TP53 variants were detected in 2%, 2.17% and 79.54% of all cases, respectively. The frequency of DDR2 mutation is nearly close to other studies, while KRAS and TP53 mutation frequencies are lower and higher than other populations, respectively. Three new putative pathogenic variants, for the first time, have been detected in Iranian patients with lung cancer, including Q808H in DDR2, F212L, and D186G in coding regions of TP53. In addition, we observed five novel benign variants, including Q167Q, P222P and T211T in coding sequence, and c.560-12A>G and c.672+86T>C, in intronic region of TP53. Mutations of KRAS and DDR2 were found in LCC and SCC subtypes, respectively, whereas mutations of TP53 were seen in SCC and ADC subtypes with higher frequencies and LCC subtype with lower frequency. Therefore, Iranian lung cancer patients can benefit from mutational analysis before starting the conventional treatment. A better understanding of the biology of these genes and their mutations will be critical for developing future targeted therapies.