Snowball‐like appearance on radial endobronchial ultrasonography in a patient with invasive mucinous adenocarcinoma

Lung invasive mucinous adenocarcinoma (IMA) is a unique histological subtype with different clinical and pathological characteristics. Despite prior genomic investigations on lung IMA, little is known about the genetic features and prognosis-related biomarkers in Chinese surgically resected lung IMA. IMA showed a distinct genetic profile, with more diversified driver mutations and co-occurrence of tumor drivers/suppressors than non-IMA. From non-IMA to mixed-IMA to pure-IMA, the frequency of EGFR (72.0 percent vs. 40.0 percent vs. 23.1 percent, p=0.002) and ALK (undetected vs. 20.0 percent vs. 26.9%, p=0.015) changes exhibited a trend of steady decline and rise, respectively. KRAS mutations were more common in pure-IMA than in mixed-IMA, however the difference was statistically insignificant (23.1 percent vs. 4.0 percent, p=0.10). Pure-IMA had a lower rate of TP53 mutation than mixed-IMA and non-IMA (23.1 percent vs. 52.0 percent vs. 56.0 percent, p=0.03). Furthermore, IMA had fewer arm-level amplifications (p=0.04) and more arm-level deletions (p=0.004) than non-IMA, with a steady drop in amplification and rise in deletion frequency from non-IMA to mixed-IMA to pure-IMA, respectively. Patients with EGFR mutations (mDFS=30.3 vs. 16.0 months, HR=0.19, P=0.027) and PI3K pathway mutations (mDFS=36.0 vs. 16.0 months, HR=0.12, P=0.023) had longer DFS than patients with poorly differentiated tumors (mDFS=14.1 vs. 28.0 months, HR=3.75, p=0.037) or KRAS mutations (mDFS=13 KRAS mutations, PI3K pathway changes, and tumor differentiation status were all shown to be independent predictors with statistically significant effects on IMA patients' clinical outcomes in multivariate analysis. Our research shed light on the genomics of Chinese lung IMA that had been surgically removed. In IMA patients with stage III illness, we also discovered many genetic characteristics that might be used as indicators for postoperative recurrence.

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Clinical Relevance of PD-L1 Expression and CD8+ T Cells’ Infiltration in Patients With Lung Invasive Mucinous Adenocarcinoma

Frontiers in Oncology ◽

10.3389/fonc.2021.683432 ◽

2021 ◽

Vol 11 ◽

Author(s):

Xiaoling Xu ◽

Na Li ◽

Ding Wang ◽

Wei Chen ◽

Yun Fan

Keyword(s):

Mucinous Adenocarcinoma ◽

Target Therapy ◽

Tumor Infiltrating Lymphocytes ◽

Egfr Mutations ◽

Chi Square ◽

Genetic Characteristics ◽

Kaplan Meier ◽

Chi Square Test ◽

Cox Proportional Hazard Regression ◽

Invasive Mucinous Adenocarcinoma

BackgroundInvasive mucinous adenocarcinoma (IMA) of the lung is a rare and distinct subtype of adenocarcinoma. At present, people have no idea whether IMA patients can benefit from immunotherapy and target therapy; thus there is an urgent need to clarify the immune microenvironment and genetic characteristics of this cohort.MethodsA total of 31 IMA patients matched with 27 non-mucinous adenocarcinoma (non-IMA) patients were enrolled in this study, and clinical data was collected. The expression of PD-L1, CD8+ tumor-infiltrating lymphocytes (TILs) and ALK was determined by immunohistochemistry. Polymerase Chain Reaction was used to determine the mutations of EGFR. The Chi-square test, Kaplan–Meier method and Cox proportional hazard regression model were used to explore the correlations between these clinicopathological variables, survival and identify risk factors.ResultsOf the patients with IMA 9.7% (3/31) revealed positive PD-L1 expression and 35.5% (11/31) showed CD8+ TIL infiltration, which were markedly lower than that of non-IMA group [PD-L1: 48.1% (13/27); CD8: 81.5% (22/27)]. Moreover, five (16.1%) patients in IMA group and 10 (37.0%) patients in non-IMA group had EGFR mutations, and nine (29.0%) patients in IMA group and zero (0.0%) patient in non-IMA group had ALK rearrangements. Additionally, we observed that IMA patients with CD8+ TIL infiltration had a worse prognosis than CD8-negative group (P = 0.024). Multivariate analyses showed that CD8 was an independent prognostic factor for patient’s survival (HR = 5.60, 95% CI: 1.35–23.22, P = 0.017).ConclusionPatients with IMA have down-regulated expression of PD-L1 and less CD8+ TIL infiltration in tumor microenvironment. Besides, a lower frequency of EGFR mutations was detected in patients with IMA than non-IMA patients while a higher rate of ALK rearrangements was found. Our results provide important reference for therapy of lung IMA.

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