Pathology and Classification of SCLC

Abstract

Lung cancer is consistently the leading cause of cancer-related death worldwide, and it ranks as the second most frequent type of new cancer cases diagnosed in the United States, both in males and females. One subtype of lung cancer, small cell lung carcinoma (SCLC), is an aggressive, poorly differentiated, and high-grade neuroendocrine carcinoma that accounts for 13% of all lung carcinomas. SCLC is the most frequent neuroendocrine lung tumor, and it is commonly presented as an advanced stage disease in heavy smokers. Due to its clinical presentation, it is typically diagnosed in small biopsies or cytology specimens, with routine immunostaining only. However, immunohistochemistry markers are extremely valuable in demonstrating neuroendocrine features of SCLC and supporting its differential diagnosis. The 2015 WHO classification grouped all pulmonary neuroendocrine carcinomas in one category and maintained the SCLC combined variant that was previously recognized. In this review, we explore multiple aspects of the pathologic features of this entity, as well as clinically relevant immunohistochemistry markers expression and its molecular characteristics. In addition, we will focus on characteristics of the tumor microenvironment, and the latest pathogenesis findings to better understand the new therapeutic options in the current era of personalized therapy.

Comprehensive analysis of prognostic predictors for patients with limited-stage small-cell lung cancer who underwent resection followed by adjuvant chemotherapy

“…In examining the genetic level and the use of NGS examinations, we found both similarities and differences in the genetic mutations of the p-SCLC and c-SCLC patients. TP53 and RB1 were the 2 most frequent mutations in both p-SCLC and c-SCLC patients, which reflects the results of a previous study (4). Additionally, both pathological subtypes shared some other similar mutations; for example, FGFR2, NOTCH1, TSC2, EGFR, and ERBB4 were highly expressed in the total SCLC cohort.…”

“…According to our analysis, among the SCLC patients who underwent resection followed by ACT treatment, the proportion of c-SCLC was almost comparable to that of p-SCLC. However, our figure was obviously larger than the figure of 28% found in a previous study (4). Notably, there were no statistical differences in relation to the clinical characteristics of the p-SCLC and c-SCLC groups, which supports the findings of Guo's and Zhang's previous research (13,14).…”

The Ubiquitin System: An Emerging Therapeutic Target for Lung Cancer

“…SCLCs usually originate in a peribronchial location with infiltration of the bronchial submucosa and peribronchial tissue [9]. Bronchial obstruction is usually caused by circumferential compression, but endobronchial lesions can occur in rare cases.…”

Immunotherapy in Extensive-Stage Small Cell Lung Cancer

“…It was discussed to be more immunogenic and defined as a distinct T-cell inflamed phenotype [22]. Eventually, it was noted that YAP1 expression was not restricted to a specific phenotype and is usually expressed in rare cases across all SCLC subtypes [21], but rather another SCLC-I subtype with low expression of transcription factors and an inflamed gene signature could be identified [23].…”