Clinical characteristics and prognostic significance of 92 cases of patients with primary mixed-histology lung cancer

Histological transformation into SCLC: An important resistance mechanism of NSCLC upon immunotherapy

The phenomenon of histological transformation has been widely reported in advanced non-small cell lung cancer (NSCLC) with EGFR mutations following the failure of EGFR-TKI treatment. Recent evidence suggests that similar histological changes can also occur in advanced NSCLC without driver gene mutations after developing resistance to immunotherapy. In this review, it was found that 66.7% of cases with immunotherapy-induced histological transformation were classified as lung squamous cell carcinoma (LSCC), while histological conversion into lung adenocarcinoma (LUAD) without EGFR or ALK gene mutations has rarely been reported. There have been sporadic reports on the occurrence of mutual transformation between LUAD and LSCC. The histological conversion from NSCLC into small cell lung cancer (SCLC) appears to be significantly underestimated, likely due to the infrequency of re-biopsy following the development of immunotherapy resistance. Several studies have reported a close association between the transformation and mutations at TP53 and the RB1 splice site, as well as the loss of an FBXW7 mutation. However, the exact mechanisms underlying this conversion remain unclear. Currently, there is a lack of guidelines for the management of transformed SCLC from NSCLC following immunotherapy, with chemotherapy being the most commonly employed treatment approach.

Pathological transition as the arising mechanism for drug resistance in lung cancer

Despite the tremendous efforts for improving therapeutics of lung cancer patients, its prognosis remains disappointing. This can be largely attributed to the lack of comprehensive understanding of drug resistance leading to insufficient development of effective therapeutics in clinic. Based on the current progresses of lung cancer research, we classify drug resistance mechanisms into three different levels: molecular, cellular and pathological level. All these three levels have significantly contributed to the acquisition and evolution of drug resistance in clinic. Our understanding on drug resistance mechanisms has begun to change the way of clinical practice and improve patient prognosis. In this review, we focus on discussing the pathological changes linking to drug resistance as this has been largely overlooked in the past decades.

Pathology Issues in Thoracic Oncology: Histologic Characterization and Tissue/Plasma Genotyping May Resolve Diagnostic Dilemmas

Lung cancer is a heterogeneous diagnosis that encompasses a spectrum of histologic and molecular subgroups. A paradigm shift favoring selection of treatment based on histologic and molecular makeup has positively affected prognosis for patients with metastatic lung cancer, with select patients experiencing durable responses to treatment. However, prognosis remains poor for the majority of patients. Furthermore, oncologists are increasingly faced with challenging dilemmas related to histopathologic and molecular characterization of tumors, both at diagnosis and during treatment. In this review, we focus on three particular challenges: (1) management of mixed histology tumors, a particularly aggressive group of lung cancers, (2) distinguishing multiple primary lung tumors from intrapulmonary metastases, and (3) incorporation of liquid biopsies into the diagnostic algorithm and subsequent follow-up of patients with advanced lung cancer. This review will summarize the existing literature and highlight the potential for molecular genotyping to help refine approaches to each of these challenges.