Solid histological component of adenocarcinoma might play an important role in PD-L1 expression of lung adenocarcinoma.

In this study we aimed to clarify the PD-L1 positive expression in lung adenocarcinoma, including various adenocarcinoma subtypes paying particular attention to its component. A total of 307 lung adenocarcinoma patients who underwent lobectomy or segmentectomy, as well as systematic lymph node dissection (ND2a), from February 2008 to March 2020 at our hospital, were enrolled into the study. A final diagnosis of adenocarcinoma was obtained from the resected lung specimens of all 307 patients to determine the histological type, adenocarcinoma subtype, and component of adenocarcinoma by ethics of 5%. PD-L1 was immunohistochemically stained using the murine monoclonal antibody clone 22C3. When PD-L1 expression-positive was defined by tumor proportion score (TPS) ≥1%, the positive cases were 6/33 in adenocarcinoma (Ad) in situ (AIS), 2/26 in minimally invasive Ad (MIA), 12/60 in lepidic predominant Ad (LPA), 44/91 in papillary predominant Ad (PPA), 24/49 in acinar predominant Ad (APA), 23/28 in solid predominant Ad (SPA), 4/7 in micropapillary predominant Ad (MPA), and 0/13 in invasive mucinous Ad (IMA). In the high proportion group (APA, PPA, SPA, and MPA) of PD-L1 expression, SPA was the only subtype which was statistically significant when both PD-L1 expression-positive was defined by TPS ≥ 1% (p < 0.0001) and TPS ≧ 50% (p < 0.0001). We then considered the solid component. We investigated 279 cases of the other subtype group excluding SPA. The group containing a solid component (≥5%) tended to be PD-L1 expression-positive both when defined by TPS ≥1% (p < 0.0001) and TPS ≧50% (p = 0.0049). The PD-L1 expression tended to be positive when a solid component was confirmed (≥5%) in specimens of lung adenocarcinoma patients.

Miyazawa T ，Morikawa K ，Otsubo K ，Sakai H ，Kimura H ，Chosokabe M ，Furuya N ，Marushima H ，Kojima K ，Mineshita M ，Koike J ，Saji H ... -  《-》

Association of Lung Adenocarcinoma Subtypes According to the IASLC/ATS/ERS Classification and Programmed Cell Death Ligand 1 (PD-L1) Expression in Tumor Cells.

Background: Programmed cell death-ligand 1 (PD-L1) protein expression is one of the most extensively studied biomarkers in patients with non-small cell lung cancer (NSCLC). However, there is scarce information regarding its association with distinct adenocarcinoma subtypes. This study evaluated the frequency of PD-L1 expression according to the IASLC/ATS/ERS classification and other relevant histological and clinical features. Patients and Methods: PD-L1 expression was assessed by immunohistochemistry (IHC). According to its positivity in tumor cells membrane, we stratified patients in three different tumor proportions score (TPS) cut-off points: a) <1% (negative), b) between 1 and 49%, and c) ≥50%; afterward, we analyzed the association among PD-L1 expression and lung adenocarcinoma (LADC) predominant subtypes, as well as other clinical features. As an exploratory outcome we evaluated if a PD-L1 TPS score ≥15% was useful as a biomarker for determining survival. Results: A total of 240 patients were included to our final analysis. Median age at diagnosis was 65 years (range 23-94 years). A PD-L1 TPS ≥1% was observed in 52.5% of the entire cohort; regarding specific predominant histological patterns, a PD-L1 TPS ≥1 was documented in 31.2% of patients with predominant-lepidic pattern, 46.2% of patients with predominant-acinar pattern, 42.8% of patients with a predominant-papillary pattern, and 68.7% of patients with predominant-solid pattern (p = 0.002). On the other hand, proportion of tumors with PD-L1 TPS ≥50% was not significantly different among adenocarcinoma subtypes. At the univariate survival analysis, a PD-L1 TPS cut-off value of ≥15% was associated with a worse PFS and OS. Conclusion: According to IASLC/ATS/ERS lung adenocarcinoma classification, the predominant-solid pattern is associated with a higher proportion of PD-L1 positive samples, no subtype was identified to be associated with a high (≥50%) TPS PD-L1.

Cruz-Rico G ，Avilés-Salas A ，Popa-Navarro X ，Lara-Mejía L ，Catalán R ，Sánchez-Reyes R ，López-Sánchez D ，Cabrera-Miranda L ，Aquiles Maldonado-Martínez H ，Samtani-Bassarmal S ，Arrieta O ... -  《-》

PD-L1 Expression in Non-Small-Cell Lung Cancer Including Various Adenocarcinoma Subtypes.

Miyazawa T ，Marushima H ，Saji H ，Kojima K ，Hoshikawa M ，Takagi M ，Nakamura H ... -  《-》

Heterogeneous components of lung adenocarcinomas confer distinct EGFR mutation and PD-L1 expression.

Cai Y ，Wu H ，Shi X ，Dong Y ，Chang X ，Zhang L ，Zhou L ，Su D ，Yang M ... -  《BMC CANCER》

Expression of PD-L1, PD-L2, and IDO1 on tumor cells and density of CD8-positive tumor-infiltrating lymphocytes in early-stage lung adenocarcinoma according to histological subtype.

Takada K ，Toyokawa G ，Kinoshita F ，Jogo T ，Kohashi K ，Wakasu S ，Ono Y ，Tanaka K ，Oba T ，Osoegawa A ，Tagawa T ，Azuma K ，Okamoto I ，Shimokawa M ，Oda Y ，Mori M ... -  《-》