Multi-site screening for Pneumocystis jirovecii in lung cancer: possible tumour tissue colonization

Area of Science:

• Medical Mycology
• Oncology
• Microbiome Research

Background:

• Emerging evidence indicates various microorganisms colonize diverse tumor types.
• Data on the opportunistic fungus Pneumocystis jirovecii (PJP) in cancer, particularly lung cancer, is limited.
• PJP is known to distribute focally within the lungs, posing a diagnostic challenge.

Purpose of the Study:

• To investigate the presence and distribution of PJP in lung tumor tissues.
• To explore the potential colonization of neoplastic lung tissue by PJP.
• To assess the relationship between PJP detection and lung cancer characteristics.

Main Methods:

• Collection of neoplastic tissue (NPL), normal adjacent tissue (NAT), and respiratory secretions (RS) from 70 lung cancer patients.
• DNA extraction and nested-PCR analysis targeting mtLSU rRNA and CYB loci for PJP detection.
• Genotyping of detected PJP strains to analyze distribution patterns.

Main Results:

• PJP was detected in 11.4% (8/70) of individuals across NPL, NAT, and RS samples.
• PJP was found in 2 neoplastic tissue samples.
• In two patients with high-grade malignancy (G3), PJP was detected in all three specimen types, with varying genotype distributions.

Conclusions:

• Pneumocystis jirovecii can colonize neoplastic lung tissue, potentially influenced by tumor advancement and microenvironment.
• Findings highlight the significance of the lung microbiome in tumor-associated microenvironments.
• Further research into the lung microbiome may offer complementary biomarkers for lung cancer diagnosis and management.