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Background: Starting with low metastatic capability, T4N0M0 (diameter ≥ 7 cm) non‐small cell lung cancers (NSCLCs) constitute a unique tumor subset, as with a large tumor size but no regional or distant metastases. We systematically investigated intratumoral heterogeneity, clonal structure, chromosomal instability (CIN), and immune microenvironment in T4N0M0 (≥7 cm) NSCLCs. Methods: Whole‐exome sequencing, RNA sequencing, and multiplex immunohistochemistry (mIHC) staining were conducted to analyze 24 spatially segregated tumor samples from eight patients who were pathologically diagnosed with T4N0M0 (diameter ≥ 7 cm) NSCLCs. The adjacent normal tissues and peripheral blood served as controls. Results: In total, 35.2% of mutations and 91.1% of somatic copy number alterations were classified as subclonal events, which exhibited widespread genetic intratumoral heterogeneity. In contrast, a low degree of CIN was observed. None of the patients had genome doubling. The burden of loss of heterozygosity, aneuploidy, and the genome instability index of these tumors were significantly lower than those in the TRACERx cohort. Expression profiles revealed significantly upregulated expression of cell division‐related signals and the G2/M checkpoint pathway. In addition, a similar expression pattern of the immune microenvironment was observed in different regions of the tumor, which was confirmed by mIHC profiles. Conclusions: Our study indicates the presence of intratumoral genetic heterogeneity and immune microenvironmental heterogeneity features in T4N0M0 NSCLCs, and the low degree of CIN may be related to the low metastatic capability. [ABSTRACT FROM AUTHOR]

Background: Src homology region 2 domain‐containing phosphatase 2 (SHP2) is a novel target for Kirsten rat sarcoma oncogene (KRAS) mutant cancer. We retrospectively studied the significance of SHP2 in KRAS mutant non‐small cell lung cancer (NSCLC) treated with immunotherapy and its relationship with tumor microenvironment (TME). Methods: Sixty‐one advanced KRAS mutant NSCLC patients who underwent immunotherapy were enrolled. Next‐generation sequencing (NGS) was used to profile mutation status. The expression of SHP2, phospho‐SHP2 (pSHP2), and programmed death ligand 1 (PD‐L1) were analyzed by immunohistochemistry (IHC). Quantitative multiplexed immunofluorescence cytochemistry (mIFC) analysis was conducted to describe the TME. Results: SHP2 was heterogeneously expressed in 32 samples in both tumor cells and immune cells and highly expressed (H‐score >10) in 25 (78.1%) samples. The expression levels of SHP2 and pSHP2 were positively correlated. Stromal SHP2 (s‐SHP2) was higher in tumors with PD‐L1 ≥50% versus PD‐L1 <50% (p = 0.039). By quantitative mIFC analysis, the expression of s‐SHP2 had positive correlation with CD8, CD4, CD68, and PD‐L1 levels in stromal area. Patients with high SHP2 expression made up 100.0% of the partial respond (PR) and 80.0% of the stable disease (SD), whereas 50.0% of the progress disease (PD). High SHP2 expression was associated with longer progression‐free survival (PFS) and overall survival (OS) (p < 0.001, p = 0.013). Patients with high expression of both SHP2 and PD‐L1 had longer PFS (p < 0.001). Conclusion: High SHP2 expression could predict the efficacy of immunotherapy and better survival in advanced KRAS mutant NSCLC. SHP2 may function in both tumor cells and immune cells, warranting further study on the potential diverse effects of SHP2 inhibition in TME. [ABSTRACT FROM AUTHOR]

Malignant pleural mesothelioma (MPM) is a rare neoplasm of the serosal membranes. MPM usually manifests as local invasion, rarely with distant haematogenous metastases in different organs. Few cases of tongue metastasis have been documented. Here, we report the case of a 68‐year‐old man diagnosed with malignant pleural epithelioid mesothelioma together with a simultaneous tongue lesion, which was found to be metastatic malignant mesothelioma. Tongue metastasis from MPM is rare and the oral symptoms it causes could be an early sign of clinical manifestation. For patients with oral symptoms and a newly discovered tongue lesion, clinicians should be aware of the possibility of tongue metastasis and search for a primary malignancy. [ABSTRACT FROM AUTHOR]

Background: ALK‐tyrosine kinase inhibitors (TKIs) have been proven effective for treating ALK‐positive non‐small cell lung cancer (NSCLC), although patients present with variable responses and disease progression courses. The detailed underlying molecular mechanisms require further investigation to yield a better prognosis. Methods: Targeted next‐generation sequencing (NGS) mutation profiling was performed on samples from 42 NSCLC patients confirmed positive for ALK rearrangements by fluorescence in situ hybridization or immunohistochemistry who experienced disease progression after crizotinib treatment. Results: ALK rearrangements were not confirmed in six patients (14%) with other potential oncogenic drivers identified by NGS, who therefore did not respond to crizotinib and had significantly shorter overall survival (OS) compared to NGS ALK ‐positive patients. Fifteen ALK activating mutations were detected in 8 out of 26 post‐treatment samples (31%), among which ALK L1196M and G1269A were the most common acquired mutations detected in half of the patients with ALK activating mutations. Dynamic monitoring of the genetic evolution in one patient revealed both spatial and temporal heterogeneity of resistant mechanisms during different ALK‐TKI treatment courses. Activation of ALK downstream or bypass pathways was detected in patients without ALK activating mutations, such as genetic alterations in PIK3CA, MET, and KRAS. Interestingly, we identified two patients with acquired mutations in the DNA mismatch repair gene POLE, which resulted in a dramatically increased tumor mutation burden, and might contribute to the poor response to crizotinib. Conclusions: Heterogeneous resistant mechanisms have been identified and correlate to diverse responses to crizotinib. Comprehensive and dynamic mutation profiling is required to better predict clinical outcomes. [ABSTRACT FROM AUTHOR]