Real-world analysis of MET exon 14 mutations in non-small cell lung cancer: a retrospective study from two Swedish hospitals.

BACKGROUND: Real-World evidence on mesenchymal-epithelial transition exon 14 skipping mutations (METex14) in lung cancer remains limited. With an incidence of 3-4% across histological subtypes, METex14 is now an actionable target for MET inhibitors (METi) in advanced lung cancer, demonstrating response rates between 30-70%. Yet, its role in early stages and sensitivity to immune checkpoint inhibitors (ICIs) is still under exploration. MATERIAL AND METHODS: We conducted a retrospective analysis of the clinical data of lung cancer patients presenting with METex14 across all stages. These patients were treated at two Swedish University Hospitals: Karolinska and Skåne, between the years 2014 and 2022. RESULTS: We identified a total of 63 patients, of which 50 met the inclusion criteria. The median overall survival (OS) with corresponding 95% confidence intervals (95% CI) according to the stage was not reached (NR) for stage I, NR for stage II, 15 months (95% CI, 5.4-24.6) for stage III, and 17 months (95% CI, 9.2-NR) for stage IV. The median OS for stage IV patients who received a METi was 17 months (95% CI, 9.5-NR) vs. 10 months (95% CI, 6.2-NR) in patients without METi (p = 0.92; Hazard Ratio [HR] = 1.07). The median OS for stage IV patients who received ICIs was 18 months (95% CI, 16.5-NR) vs. 6 months (95% CI, 2.5-NR) in patients without ICIs (p = 0.15; HR = 0.47). The median OS for stage IV patients who received chemotherapy was 17 months (95% CI, 9.7-NR) vs. 10 months (95% CI, 4.5-NR) in patients without (p = 0.97; HR = 0.98). CONCLUSIONS: Our data suggest limited survival benefits from METi, ICIs, and chemotherapy for METex14 lung cancer patients. While not statistically significant, these findings underscore the need for larger trials for validation. Identifying effective treatments for this challenging lung cancer subtype remains a priority.

Clinicopathological significance of the expression of PD-L1 in non-small cell lung cancer.

INTRODUCTION: PD1/PD-L1 pathway targeting therapies are nowadays an established treatment option for patients with NSCLC. We assessed whether PD-L1 expression in NSCLC tumor cells was associated with specific clinical features or overall survival using four different clones. METHODS AND RESULTS: A retrospective study included formalin-fixed paraffin embedded (FFPE) surgical tumors from 482 patients. PD-L1 status was assessed with immunohistochemistry in tumor cells on tissue microarrays using clones 28-8, 22C3, SP263 and SP142. Associations with OS were assessed by Kaplan-Meier and multivariate Cox's regression analysis. Patients' median age: 68 years (39-86); histology: adenocarcinoma (AdCa) 61%, squamous-cell carcinoma (SqCC) 33%, and large cell carcinoma (LCC) 6%; p-stage: IA (46%), IB (30%), IIA (10%), IIB (11,4%), IIIA (1,2%), IIIB - IV (0,4%). PD-L1 positivity (≥1%) in NSCLC for clones 28-8, 22C3, SP263, SP142 was 41.5%, 34.2%, 42.7%, 10.4%, respectively (Pearson Chi-square p < 0.0001). PD-L1 expression was correlated with histology, tumor size and grading. Statistically significant association between PD-L1 expression and OS in NSCLC and Non-AdCa was observed with clone SP142 (log-rank p = 0.045 and p = 0.05, respectively). Statistically significant association between PD-L1 expression and OS in LCC was observed with clones 22C3 (log-rank p = 0.009) and SP263 (log-rank p = 0.050). CONCLUSIONS: Overexpression of the PD-L1 clone SP142 was associated with poor overall survival in NSCLC and Non-AdCa. Clones 22C3 and SP263 were associated with poor prognosis in LCC. PD-L1 status might serve as a prognostic marker in NSCLC.

Accumulation of tissue-resident natural killer cells, innate lymphoid cells, and CD8+ T cells towards the center of human lung tumors.

Lung cancer is a leading cause of cancer-related death worldwide. Despite recent advances in tissue immunology, little is known about the spatial distribution of tissue-resident lymphocyte subsets in lung tumors. Using high-parameter flow cytometry, we identified an accumulation of tissue-resident lymphocytes including tissue-resident NK (trNK) cells and CD8+ tissue-resident memory T (TRM) cells toward the center of human non-small cell lung carcinomas (NSCLC). Chemokine receptor expression patterns indicated different modes of tumor-infiltration and/or residency between trNK cells and CD8+ TRM cells. In contrast to CD8+ TRM cells, trNK cells and ILCs generally expressed low levels of immune checkpoint receptors independent of location in the tumor. Additionally, granzyme expression in trNK cells and CD8+ TRM cells was highest in the tumor center, and intratumoral CD49a+CD16- NK cells were functional and responded stronger to target cell stimulation than their CD49a- counterparts, indicating functional relevance of trNK cells in lung tumors. In summary, the present spatial mapping of lymphocyte subsets in human NSCLC provides novel insights into the composition and functionality of tissue-resident immune cells, suggesting a role for trNK cells and CD8+ TRM cells in lung tumors and their potential relevance for future therapeutic approaches.