P14/ARF-positive malignant pleural mesothelioma

ǂa ǂphenotype with distinct immune microenvironment

Federica Pezzuto (Author), Francesca Lunardi (Author), Luca Vedovelli (Author), Francesco Fortarezza (Author), Loredana Urso (Author), Federica Grosso (Author), Giovanni Luca Ceresoli (Author), Izidor Kern (Author), Gregor Vlačić (Author), Fiorella Calabrese (Author)

Abstract

Introduction: The CDKN2A gene plays a central role in the pathogenesis of malignant pleural mesothelioma (MPM). The gene encodes for two tumor suppressor proteins, p16/INK4A and p14/ARF, frequently lost in MPM tumors. The exact role of p14/ARF in MPM and overall its correlation with the immune microenvironment is unknown. We aimed to determine whether there is a relationship between p14/ARF expression, tumor morphological features, and the inflammatory tumor microenvironment. Methods: Diagnostic biopsies from 76 chemo-naive MPMs were evaluated. Pathological assessments of histotype, necrosis, inflammation, grading, and mitosis were performed. We evaluated p14/ARF, PD-L1 (tumor proportion score, TPS), and Ki-67 (percentage) by immunohistochemistry. Inflammatory cell components (CD3+, CD4+, CD8+ T lymphocytes; CD20+ B-lymphocytes; CD68+ and CD163+ macrophages) were quantified as percentages of positive cells, distinguishing between intratumoral and peritumoral areas. The expression of p14/ARF was associated with several clinical and pathological characteristics. A random forest-based machine-learning algorithm (Boruta) was implemented to identify which variables were associated with p14/ARF expression. Results: p14/ARF was evaluated in 68 patients who had a sufficient number of tumor cells. Strong positivity was detected in 14 patients (21%) (11 epithelioid and 3 biphasic MPMs). At univariate analysis, p14/ARF-positive epithelioid mesotheliomas showed higher nuclear grade (G3) (p = 0.023) and higher PD-L1 expression (≥50%) (p = 0.042). The percentages of CD4 and CD163 in peritumoral areas were respectively higher and lower in p14/ARF positive tumors but did not reach statistical significance with our sample size (both p = 0.066). The Boruta algorithm confirmed the predictive value of PD-L1 percentage for p14/ARF expression in all histotypes. Conclusions: p14/ARF-positive epithelioid mesotheliomas may mark a more aggressive pathological phenotype (higher nuclear grade and PD-L1 expression). Considering the results regarding the tumor immune microenvironment, p14/ARF-negative tumors seem to have an immune microenvironment less sensitive to immune checkpoint inhibitors, being associated with low PD-L1 and CD4 expression, and high CD163 percentage. The association between p14/ARF-positive MPMs and PD-L1 expression suggests a possible interaction of the two pathways. Confirmation of our preliminary results could be important for patient selection and recruitment in future clinical trials with anticancer immunotherapy.

Keywords

maligni plevralni mezoteliom;malignant pleural mesothelioma;

Data

Language:	English
Year of publishing:	2022
Typology:	1.01 - Original Scientific Article
Publisher:	Frontiers
UDC:	616
COBISS:	103281667
ISSN:	2234-943X
Views:	116
Downloads:	88
Average score:	0 (0 votes)
Metadata:

Other data

Secondary keywords:	Neoplasms;Lung;Pathology;Cytology;Mesothelioma, malignant;Tumor microenvironment;Novotvorbe;Pljuča;Patologija;Citologija;Maligni mezoteliom;Tumorsko mikrookolje;
Source comment:	Nasl. z nasl. zaslona; Soavtorja iz Slovenije: Izidor Kern, Gregor Vlačić; Opis vira z dne 4. 4. 2022;
Pages:	str. 30-39
Issue:	ǂVol. ǂ11
Chronology:	22 Mar. 2022
DOI:	10.3389/fonc.2021.653497
ID:	15468537