Detailed Characterization of the Lung-Gut Microbiome Axis Reveals the Link between PD-L1 and the Microbiome in Non-Small-Cell Lung Cancer Patients

Next-generation sequencing technologies have started a new era of respiratory tract research in recent years. Alterations in the respiratory microbiome between healthy and malignant conditions have been revealed. However, the composition of the microbiome varies among studies, even in similar medical conditions. Also, there is a lack of complete knowledge about lung-gut microbiome interactions in lung cancer patients. The aim of this study was to explore the lung-gut axis in non-small-cell lung cancer (NSCLC) patients and the associations between lung-gut axis microbiota and clinical parameters (CRP, NLR, LPS, CD8, and PD-L1). Lung tissue and fecal samples were used for bacterial 16S rRNA sequencing. The results revealed, for the first time, that the bacterial richness in lung tumor tissue gradually decreased with an increase in the level of PD-L1 expression (p < 0.05). An analysis of β-diversity indicated a significant positive correlation between the genera Romboutsia and Alistipes in both the lung tumor biopsies and stool samples from NSCLC patients (p < 0.05). Survival analysis showed that NSCLC patients with higher bacterial richness in their stool samples had prolonged overall survival (HR: 2.06, 95% CI: 1.025-4.17, p = 0.0426).

Microbiota Diversity in Non-Small Cell Lung Cancer Gut and Mouth Cavity Microbiota Diversity in Non-Small Cell Lung Cancer Patients

Lung malignancies have a substantial impact on cancer incidence and mortality worldwide. Even though many factors involved in the development of the disease are known, many questions remain unanswered. Previous studies suggest that the intestinal microbiota may have a role in developing malignant diseases. According to some findings, the microbiota has proven to be a key modulator of carcinogenic processes and the immune response against cancer cells, potentially influencing the effectiveness of immunotherapy. In our study, we characterized culturable microorganisms associated with non-small cell lung cancer (NSCLC) that can be recovered from rectal swabs and mouthwash. In addition, we also explored differences in the culturable microbiota with two main types of NSCLC - adenocarcinoma (ADC) and squamous cell carcinoma (SCC). With 141 patients included in the study (86 ADC and 55 SCC cases), a significant difference was observed between the two types in seven bacterial species (Collinsella, Corynebacterium, Klebsiella, Lactobacillus, Neisseria, Rothia, and Streptococcus), including the site of origin. The relationship between microbial dysbiosis and lung cancer is poorly understood; future research could shed light on the links between gut microbiota and lung cancer development.

Gut Microbiota in Lung Cancer: Where Do We Stand?

The gut microbiota (GM) is considered to constitute a powerful "organ" capable of influencing the majority of the metabolic, nutritional, physiological, and immunological processes of the human body. To date, five microbial-mediated mechanisms have been revealed that either endorse or inhibit tumorigenesis. Although the gastrointestinal and respiratory tracts are distant physically, they have common embryonic origin and similarity in structure. The lung microbiota is far less understood, and it is suggested that the crosslink between the human microbiome and lung cancer is a complex, multifactorial relationship. Several pathways linking their respective microbiota have reinforced the existence of a gut-lung axis (GLA). Regarding implications of specific GM in lung cancer therapy, a few studies showed that the GM considerably affects immune checkpoint inhibitor (ICI) therapy by altering the differentiation of regulatory T cells and thus resulting in changes in immunomodulation mechanisms, as discovered by assessing drug metabolism directly and by assessing the host immune modulation response. Additionally, the GM may increase the efficacy of chemotherapeutic treatment in lung cancer. The mechanism underlying the role of the GLA in the pathogenesis and progression of lung cancer and its capability for diagnosis, manipulation, and treatment need to be further explored.

Characteristics of pathogenic microbes in lung microenvironment of lung cancer patients without respiratory infection

PURPOSE

The characteristics of pathogenic microbes are useful for understanding the microbe-driven tumorigenesis. There is a lack of studies on the lung microecology for lung cancer (LC) patients without any respiratory infection. In this work, we aimed to describe the profiles of pathogenic microbes in lung microenvironment of non-small cell lung cancer (NSCLC) patients using pathogen targeted sequencing and 16S rDNA sequencing.

METHODS

A total of 22 NSCLC patients (13 adenocarcinomas and 9 squamous cell carcinomas) without any pulmonary infection were enrolled. Among them, we collected 15 pieces of tumor tissues, 5 pieces of peritumoral tissues, 6 blood serum samples, and 5 broncho-alveolar lavage fluid (BALF) samples. Pathogen targeted sequencingand16S rDNA sequencing was performed for microbial classification.

RESULTS

The pathogen targeted sequencing results showed that 33, 14, 11, and 27 pathogenic microorganisms were detected in tumor tissues, peritumoral tissues, blood samples, and BALF, respectively. No common microorganisms were shared by four sample types. However, some common elements were shared by three sets: Streptococcus cristatus, Enterococcus, Staphylococcus haemolyticus, Corynebacterium pseudodiphtheria, Acinetobacter jungii, Haemophilus haemolyticus and Haemophilus parainfluenzae. Based on the 16S rDNA sequencing of two BALF samples, there were 104 OTUs found in one BALF sample and 127 OTUs in the other BALF sample; among them, there were 82 common ones, such as OTU1, OTU10, OTU101, OTU105, OTU106, and so on. Based on the above microbial classification and abundance, there might be enriched function in COG terms like COG1132, COG0438 and COG0745, and KEGG terms like K06147, K02029, and K09687.

CONCLUSION

This study emphasizes the role of the microbiome in LC patients without respiratory infection. These potential biomarkers of LC based on the taxonomic composition of pathogenic microorganisms might have clinical application.

Non-small cell lung cancer microbiota characterization: Prevalence of enteric and potentially pathogenic bacteria in cancer tissues

Following recent findings linking the human gut microbiota to gastrointestinal cancer and its treatment, the plausible relationship between lung microbiota and pulmonary cancer is explored. This study aims at characterizing the intratumoral and adjacent healthy tissue microbiota by applying a 16S rRNA gene amplicon sequencing protocol to tissue samples of 29 non-small cancer patients. Emphasis was put on contaminant management and a comprehensive comparison of bacterial composition between cancerous and healthy adjacent tissues of lung adenocarcinoma and squamous cell carcinoma is provided. A variable degree of similarity between the two tissues of a same patient was observed. Each patient seems to possess its own bacterial signature. The two types of cancer tissue do not have a distinct bacterial profile that is shared by every patient. In addition, enteric, potentially pathogenic and pro-inflammatory bacteria were more frequently found in cancer than healthy tissue. This work brings insights into the dynamic of bacterial communities in lung cancer and provides prospective data for more targeted studies.

Colonization with multi-drug-resistant organisms negatively impacts survival in patients with non-small cell lung cancer

Objectives

Multidrug-resistant organisms (MDRO) are considered an emerging threat worldwide. Data covering the clinical impact of MDRO colonization in patients with solid malignancies, however, is widely missing. We sought to determine the impact of MDRO colonization in patients who have been diagnosed with Non-small cell lung cancer (NSCLC) who are at known high-risk for invasive infections.

Materials and methods

Patients who were screened for MDRO colonization within a 90-day period after NSCLC diagnosis of all stages were included in this single-center retrospective study.

Results

Two hundred and ninety-five patients were included of whom 24 patients (8.1%) were screened positive for MDRO colonization (MDRO^pos) at first diagnosis. Enterobacterales were by far the most frequent MDRO detected with a proportion of 79.2% (19/24). MDRO colonization was present across all disease stages and more present in patients with concomitant diabetes mellitus. Median overall survival was significantly inferior in the MDRO^pos study group with a median OS of 7.8 months (95% CI, 0.0–19.9 months) compared to a median OS of 23.9 months (95% CI, 17.6–30.1 months) in the MDRO^neg group in univariate (p = 0.036) and multivariate analysis (P = 0.02). Exploratory analyses suggest a higher rate of non-cancer-related-mortality in MDRO^pos patients compared to MDRO^neg patients (p = 0.002) with an increased rate of fatal infections in MDRO^pos patients (p = 0.0002).

Conclusions

MDRO colonization is an independent risk factor for inferior OS in patients diagnosed with NSCLC due to a higher rate of fatal infections. Empirical antibiotic treatment approaches should cover formerly detected MDR commensals in cases of (suspected) invasive infections.

Network Analysis of Gut Microbiome and Metabolome to Discover Microbiota-Linked Biomarkers in Patients Affected by Non-Small Cell Lung Cancer

Several studies in recent times have linked gut microbiome (GM) diversity to the pathogenesis of cancer and its role in disease progression through immune response, inflammation and metabolism modulation. This study focused on the use of network analysis and weighted gene co-expression network analysis (WGCNA) to identify the biological interaction between the gut ecosystem and its metabolites that could impact the immunotherapy response in non-small cell lung cancer (NSCLC) patients undergoing second-line treatment with anti-PD1. Metabolomic data were merged with operational taxonomic units (OTUs) from 16S RNA-targeted metagenomics and classified by chemometric models. The traits considered for the analyses were: (i) condition: disease or control (CTRLs), and (ii) treatment: responder (R) or non-responder (NR). Network analysis indicated that indole and its derivatives, aldehydes and alcohols could play a signaling role in GM functionality. WGCNA generated, instead, strong correlations between short-chain fatty acids (SCFAs) and a healthy GM. Furthermore, commensal bacteria such as Akkermansia muciniphila, Rikenellaceae, Bacteroides, Peptostreptococcaceae, Mogibacteriaceae and Clostridiaceae were found to be more abundant in CTRLs than in NSCLC patients. Our preliminary study demonstrates that the discovery of microbiota-linked biomarkers could provide an indication on the road towards personalized management of NSCLC patients.

The association between gut butyrate-producing bacteria and non-small-cell lung cancer

BACKGROUND

Recently, it has been found that the gut microbiota may affect the development of lung cancer through the "gut-lung axis." To investigate this relationship, we performed this study to determine whether the gut microbiota in non-small-cell lung cancer (NSCLC) patients is different from that in healthy adults.

METHODS

Quantitative PCR (qPCR) was used to detect the expression levels of eight gut butyrate-producing bacteria in healthy adults and NSCLC patients. We enrolled 30 patients with NSCLC and 30 subjects from 100 healthy adults after matching for age and sex.

RESULTS

Compared to healthy adults, most of the gut butyrate-producing bacteria in NSCLC patients were significantly decreased; these included Faecalibacterium prausnitzii, Clostridium leptum, Clostridial cluster I, Ruminococcus spp., Clostridial Cluster XIVa, and Roseburia spp. Among the gut butyrate-producing bacteria, we analyzed Clostridial cluster IV and Eubacterium rectale were not decreased in NSCLC patients.

CONCLUSIONS

We conclude that NSCLC patients had gut butyrate-producing bacteria dysbiosis. Further studies should be performed to investigate the underlying mechanisms of how these specific bacteria affect lung cancer progression and prognosis.

Role of antibiotic use, plasma citrulline and blood microbiome in advanced non-small cell lung cancer patients treated with nivolumab

BACKGROUND

Recent data suggested a role of gut microbiota and antibiotic use on immune checkpoint inhibitors efficacy. We aimed to evaluate the impact of early use of antibiotic (EUA), blood microbiome and plasmatic citrulline (marker of the intestinal barrier) on nivolumab efficacy in non-small cell lung cancer (NSCLC).

METHODS

We included all consecutive patients with advanced NSCLC treated with nivolumab in our Department between 2014 and 2017. Blood microbiome was analyzed at month (M) M0 and M2. Citrulline rates were evaluated at M0, M2, M4 and M6.

RESULTS

Seventy-two patients were included (EUA in 42%). Overall survival (OS) was longer without EUA (median 13.4 months) than with EUA (5.1 months, p = 0.03). Thirty-five patients (49%) had plasma samples available. High citrulline rate (≥20 μM) at M0 was associated with tumor response (p = 0.084) and clinical benefit (nivolumab > 6 months) (p = 0.002). Median progression-free survival (PFS) was 7.9 months (high citrulline) vs 1.6 months (low citrulline) (p < 0.0001), and median OS were respectively non reached vs 2.2 months (p < 0.0001). Patients with EUA had lower median citrulline rates at M0: 21 μM (IQR 15.0-30.8) vs 32 μM (IQR 24.0-42.0) without EUA (p = 0.044). The presence of specific bacterial DNA in blood at M0 was associated with response and clinical benefit (Peptostreptococcae, Paludibaculum, Lewinella) or with tumor progression (Gemmatimonadaceae). Multivariate analyses on PFS and OS confirmed the prognostic role of citrulline and blood microbiome.

CONCLUSIONS

EUA is associated with shorter OS with nivolumab and lower citrulline rates. Plasma citrulline and blood microbiome appear to be promising predictive factors of nivolumab efficacy.

A repository of microbial marker genes related to human health and diseases for host phenotype prediction using microbiome data

The microbiome research is going through an evolutionary transition from focusing on the characterization of reference microbiomes associated with different environments/hosts to the translational applications, including using microbiome for disease diagnosis, improving the effcacy of cancer treatments, and prevention of diseases (e.g., using probiotics). Microbial markers have been identified from microbiome data derived from cohorts of patients with different diseases, treatment responsiveness, etc, and often predictors based on these markers were built for predicting host phenotype given a microbiome dataset (e.g., to predict if a person has type 2 diabetes given his or her microbiome data). Unfortunately, these microbial markers and predictors are often not published so are not reusable by others. In this paper, we report the curation of a repository of microbial marker genes and predictors built from these markers for microbiome-based prediction of host phenotype, and a computational pipeline called Mi2P (from Microbiome to Phenotype) for using the repository. As an initial effort, we focus on microbial marker genes related to two diseases, type 2 diabetes and liver cirrhosis, and immunotherapy efficacy for two types of cancer, non-small-cell lung cancer (NSCLC) and renal cell carcinoma (RCC). We characterized the marker genes from metagenomic data using our recently developed subtractive assembly approach. We showed that predictors built from these microbial marker genes can provide fast and reasonably accurate prediction of host phenotype given microbiome data. As understanding and making use of microbiome data (our second genome) is becoming vital as we move forward in this age of precision health and precision medicine, we believe that such a repository will be useful for enabling translational applications of microbiome data.

Characterisation of gut, lung, and upper airways microbiota in patients with non-small cell lung carcinoma: Study protocol for case-control observational trial

BACKGROUND

Several studies have confirmed the important role of the gut microbiota in the regulation of immune functions and its correlation with different diseases, including cancer. While brain-gut and liver-gut axes have already been demonstrated, the existence of a lung-gut axis has been suggested more recently, with the idea that changes in the gut microbiota could affect the lung microbiota, and vice versa. Likewise, the close connection between gut microbiota and cancer of proximal sites (intestines, kidneys, liver, etc.) is already well established. However, little is known whether there is a similar relation when looking at world's number one cause of death from cancer-lung cancer.

OBJECTIVE

Firstly, this study aims to characterise the gut, lung, and upper airways (UAs) microbiota in patients with non-small cell lung cancer (NSCLC) treated with surgery or neoadjuvant chemotherapy plus surgery. Secondly, it aims to evaluate a chemotherapy effect on site-specific microbiota and its influence on immune profile. To our knowledge, this is the 1st study that will analyse multi-site microbiota in NSCLC patients along with site-specific immune response.

METHODS

The study is a case-controlled observational trial. Forty NSCLC patients will be divided into 2 groups depending on their anamnesis: Pchir, patients eligible for surgery, or Pct-chir, patients eligible for neoadjuvant chemotherapy plus surgery. Composition of the UAs (saliva), gut (faeces), and lung microbiota (from broncho-alveolar lavage fluid (BALF) and 3 lung pieces: "healthy" tissue distal to tumour, peritumoural tissue and tumour itself) will be analysed in both groups. Immune properties will be evaluated on the local (evaluation of the tumour immune cell infiltrate, tumour classification and properties, immune cell phenotyping in BALF; human neutrophil protein (HNP) 1-3, β-defensin 2, and calprotectin in faeces) and systemic level (blood cytokine and immune cell profile). Short-chain fatty acids (SCFAs) (major products of bacterial fermentation with an effect on immune system) will be dosed in faecal samples. Other factors such as nutrition and smoking status will be recorded for each patient. We hypothesise that smoking status and tumour type/grade will be major factors influencing both microbiota and immune/inflammatory profile of all sampling sites. Furthermore, due to non-selectivity, the same effect is expected from chemotherapy.

Role of C-reactive protein and procalcitonin in discriminating between infectious fever and tumor fever in non-neutropenic lung cancer patients

This study assessed whether C-reactive protein (CRP) and procalcitonin (PCT) levels can discriminate between infectious fever and tumor fever (TF) in non-neutropenic patients with nonsmall cell lung cancer (NSCLC).This retrospective clinical study included 96 adults with NSCLC who were admitted to the Third Hospital of Hebei Medical University between July 2015 and July 2017. Febrile, non-neutropenic patients were enrolled. CRP and PCT levels, neutrophil count, and antimicrobial response were evaluated.This study included 26 patients with TF, 49 with localized bacterial infection (LBI), and 21 with bloodstream infection (BSI). CRP levels in BSI were significantly higher than in TF (P < .05) and LBI (P < .05). No statistically significant difference was found between patients with TF and LBI (P > .05). PCT levels were significantly higher in BSI and LBI than in TF (P < .05). CRP and PCT levels in patients with stage IV disease were significantly higher than in those with stage II to III disease (P < .05). CRP and PCT levels declined significantly in patients with BSI who were responding to antimicrobials (P < .05).Compared with CRP levels, PCT levels can discriminate between TF and infectious fever more accurately. PCT and CRP levels may predict different stages of lung cancer.

Methicillin-Resistant Staphylococcus Aureus infection exacerbates NSCLC cell metastasis by up-regulating TLR4/MyD88 pathway

Methicillin-resistant Staphylococcus aureus (MRSA) infection is a major public health problem worldwide, which brings to a more great threat for cancer patients. It's necessary to give attentions to lung cancer combined with MRSA. This study mainly focuses on the influences of MRSA on lung cancer cells (A549). We first found that MRSA infection can enhance metastasis ability of A549 cell and increase matrix metalloproteinase (MMP2 and MMP9) expressions in MRSA-infected A549 cell. Toll-like receptors (TLRs) have been reported to play an important role in tumor cell initiation and migration, and regulate the expression of MMPs in tumors. Our further research indicates that Toll-like receptor 4 (TLR4)/molecules myeloid differentiation factor 88 (MyD88) signaling was up-regulated in MRSA-infected A549 cell. After silencing TLR4 or MyD88 gene, the enhanced metastasis ability of A549 cell by MRSA was decreased significantly; Also, MMP2 and MMP9 expression increase was reversed. In conclusion, MRSA infection can enhance NSCLC cell metastasis by up-regulating TLR4/MyD88 signaling.

Differentiation by random amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR) of Candida albicans isolated from upper respiratory tract in patients with non-small cell lung cancer

Cancer patients are predisposed to fungal infections caused by Candida albicans, especially to oral or respiratory tract candidiasis. The aim of this study was to estimate genetic diversity by RAPD-PCR (random amplified polymorphic DNA-polymerase chain reaction) of C. albicans isolated from upper respiratory tract of 100 patients with non-small cell lung cancer. Among 52 strains, 34 genotypes were defined. 10 clusters comprising 28 (53.85%) isolates with similarity coefficient ≥ 80% were formed. The remaining 24 (46.15%) isolates represented individual genotypes. The RAPD-PCR technique revealed genomic variability within C. albicans isolated from upper respiratory tract of the cancer patients.

Bacterial colonization of pleural drains in patients with lung cancer: an analysis of risk factors

BACKGROUND

Microbial colonization of pleural drains during the postoperative period may be regarded as an important factor in infection development. The aim of this paper was to determine the frequency and risk factors associated with microbial colonization of pleural drains in patients with non-small-cell lung cancer (NSCLC) who underwent surgical resection.

MATERIAL/METHODS

A total of 72 pleural drain fluids obtained from 36 patients with NSCLC were microbiologically examined.

RESULTS

Microbial colonization of pleural drain fluid was noted in 30/36 patients (83.34%). Aerobic and anaerobic bacteria were found in 13 (36.11%) and 7 (19.44%) patients, respectively, and mixed microflora were cultured from 9 (25%). Non-fermentative gram-negative rods and coagulase-negative staphylococci were mainly isolated. Univariate analysis revealed that FEV1% >65 and FEV1/FVC were significantly related to drain colonization by bacteria in general, FEV1/FVC to colonization by aerobic bacteria, and hospitalization >5 days before surgery to colonization by anaerobic bacteria. According to multivariate analysis, application of antibiotic prophylaxis other than cefuroxime or ceftriaxone and FEV1% >65 were the independent factors related to drain colonization by bacteria in general; antibiotic prophylaxis other than cefuroxime or ceftraixone alone and hospitalization >5 days before surgery to colonization by anaerobic bacteria; and a higher rate of FEV1/FVC, no chemotherapy before surgery, and postsurgical complications after surgery to colonization by aerobic bacteria.

CONCLUSIONS

Patients with resectable lung cancer showed a high rate of pleural drain colonization, mainly by opportunistic pathogens, even in the absence of clinical signs of infection.

Evaluation of infections in non-small cell lung cancer patients treated with radiotherapy

PURPOSE

We aim to determine infections occurring in patients with non-small cell lung cancer during radiotherapy (RT).

METHODS AND MATERIALS

A total of 181 patients had been treated with thoracic radiotherapy between October 1995 and December 1999. Radiotherapy was given using 1.8-3Gray (Gy) fraction daily, five fractions a week for a total dose of 59.4Gy (30-70.2Gy). A complete history was collected retrospectively for each patient. All microbiological examinations were performed according to the routine procedures of the hospital laboratory. Numeric and categoric variables were employed such as sex, age, performance status, histology, stage, chemotherapy, usage of corticosteroids, neutropenia, surgery, hospitalization, associated diseases, smoking during treatment, package per year of cigarette smoking, dose of radiotherapy, and response rates.

RESULTS

Infections developed in 84 patients (46%, 84/181) during thoracic radiotherapy. A 101 episodes of infections developed in these patients. Most patients suffered from sputum production (65%), cough (59%), auscultation findings (31%) and fever (31%). Gram-negative bacteria were the most frequently isolated pathogens in the cultures of specimens (70%, 16/23 samples). Neoadjuvant chemotherapy (OR=4.81; 95% CI, 1.57-9.12; p=0.003) and neutropenia (OR=4.25; 95% CI, 1.44-6.89; p=0.009) were found as risk factors for influencing infection based on logistic regression analyses. Package per year of cigarette smoking was found statistically significantly higher in patients with infections than patients without infections (p=0.001). A slight increase in infections, which was of borderline statistical significance (p=0.07), was observed in patients age over 70. Ciprofloxacin and clarithromycin were the most frequently used agents in treatment. Median survival was 9 months in the patients with infection and 13 months in the 97 patients without infection. Overall survival seemed to be statistically significantly better in patients without infection than patients with infection (p=0.042) calculated using Kaplan-Meier method. Based on Cox regression analyses; overall survival was not correlated to presence of infection but associated with poor performance status (</=80) (OR=2.35; 95% CI, 0.85-8.93; p=0.03), and usage of corticosteroids (OR=2.68; 95% CI, 0.98-6.72; p=0.01). The dose of radiation therapy >5940 cGy (OR=2.06; 95% CI, 0.72-7.18; p=0.007) and the absence of response to treatment (OR=2.45; 95% CI, 0.89-14.23; p<0.001) were also found to be risk factors for survival.

CONCLUSIONS

Infections are important causes of morbidity and mortality in lung cancer patients. The control of infection in these patients may improve the survival. Predisposing factors and treatment management approaches in non-small cell lung cancer should be defined carefully.

Does Helicobacter pylori infection play a role in lung cancer?

BACKGROUND

Helicobacter pylori infection is a world-wide common disease and leads to many gastrointestinal and respiratory illnesses. It is suggested that one of these respiratory illnesses is lung cancer.

METHODS

Forty-three patients with non-small cell lung cancer and 28 control subjects have been included to this study. H. pylori status of the patients and controls was determined by immunoblot for the detection of IgG (RIDA Blot Helicobacter). All subjects were examined to evaluate the presence of VacA and CagA gene.

RESULTS

Seropositivity of anti H. pylori IgG was significantly higher in cancer patients than in control groups, 40 (93%) and 12 (42%), respectively (P<0.01). Although both VacA and CagA seropositivity was high in lung cancer patients, only VacA positivity was statistically significant when compared with control subjects, 35 (81%) and 11 (42%), respectively (P<0.05).

CONCLUSION

H. pylori infection may be associated with development of lung cancer.

Association between human-Pneumocystis infection and small-cell lung carcinoma

BACKGROUND

Tobacco smoking is the most important but not the only risk factor in lung carcinoma. There is evidence that certain infections, which cause chronic inflammatory reactions, can also induce tumour development. It has recently been shown that patients with chronic pulmonary diseases present a high rate of subclinical Pneumocystis infection, and that the latter is able to induce inflammatory responses and alveolar cell alterations. The possible role of Pneumocystis infection in the development of lung neoplasms thus deserves consideration.

MATERIAL AND METHODS

Polymerase chain reaction has been used to analyze the presence of DNA of two independent loci of the Pneumocystis genome: the mitochondrial region (mtLSU rRNA) and the gene encoding for the dihydropteroate synthase enzyme, in paraffin-embedded tissue blocks of 10 cases of small cell lung carcinoma (SCLC) and 10 cases of nonsmall cell lung carcinoma (NSCLC) with similar demographic and clinical characteristics. Five cases without lung pathology, and two cases of Pneumocystis pneumonia were also analyzed as controls.

RESULTS

DNA of the microorganism was found in all the cases of SCLC but in only two of the NSCLC, and in none of the controls without pulmonary disease - thus implying a statistically significant association (P < 0.0001) between subclinical Pneumocystis infection and SCLC.

CONCLUSIONS

While the nature of this association is not clear, it nevertheless constitutes an important finding - either the infection is specifically facilitated by this tumour or induces the development of this type of neoplasm in combination with other factors. Eur J Clin Invest 2004; 34 (3): 229-335

Lung cancer occurring with Mycobacterium xenopi and Aspergillus

Two cases which associate Mycobacterium xenopi pulmonary infection, aspergilloma and preoperative unsuspected lung cancer are related. To our knowledge, the association of these three pathologies has never been previously reported. These two cases, suggest that infected chronic lung lesions, especially in smokers, should be closely monitored and be surgically removed in order to prevent further complications.

Identification of Helicobacter pylori and other Helicobacter species by PCR, hybridization, and partial DNA sequencing in human liver samples from patients with primary sclerosing cholangitis or primary biliary cirrhosis

Helicobacter pylori was identified in human liver tissue by PCR, hybridization, and partial DNA sequencing. Liver biopsies were obtained from patients with primary sclerosing cholangitis (n = 12), primary biliary cirrhosis (n = 12), and noncholestatic liver cirrhosis (n = 13) and (as controls) normal livers (n = 10). PCR analyses were carried out using primers for the Helicobacter genus, Helicobacter pylori (the gene encoding a species-specific 26-kDa protein and the 16S rRNA), Helicobacter bilis, Helicobacter pullorum, and Helicobacter hepaticus. Samples from patients with primary biliary cirrhosis and primary sclerosing cholangitis (11 and 9 samples, respectively) were positive by PCR with Helicobacter genus-specific primers. Of these 20 samples, 8 were positive with the 16S rRNA primer and 9 were positive with the 26-kDa protein primer of H. pylori. These nine latter samples were also positive by Southern blot hybridization for the amplified 26-kDa fragment, and four of those were verified to be H. pylori by partial 16S rDNA sequencing. None of the samples reacted with primers for H. bilis, H. pullorum, or H. hepaticus. None of the normal livers had positive results in the Helicobacter genus PCR assay, and only one patient in the noncholestatic liver cirrhosis group, a young boy who at reexamination showed histological features suggesting primary sclerosing cholangitis, had a positive result in the same assay. Helicobacter positivity was thus significantly more common in patients with cholestatic diseases (20 of 24) than in patients with noncholestatic diseases and normal controls (1 of 23) (P = <0.00001). Patients positive for Helicobacter genus had significantly higher values of alkaline phosphatases and prothrombin complex than Helicobacter-negative patients (P = 0.0001 and P = 0.0003, respectively). Among primary sclerosing cholangitis patients, Helicobacter genus PCR positivity was weakly associated with ulcerative colitis (P = 0.05). Significant differences related to blood group or HLA status were not found.

Long-term antimicrobial prophylaxis in lung cancer surgery: correlation between microbiological findings and empyema development

This study was planned in order to determine the value of antimicrobial prophylaxis in preventing post-operative empyema in patients undergoing lung cancer surgery. Two-hundred consecutive subjects operated upon for lung cancer received teicoplanin and aztreonam, starting at the induction of anesthesia and lasting until removal of the pleural drains. Cultures for aerobic and anaerobic bacteria were taken from: (1) the bronchus at the time of surgical division; (2) the pleural space before closure of the chest; (3) the pleural fluid during the post-operative period; and (4) the tips of chest drains at the time of their removal. In the 200 patients receiving antibiotic prophylaxis, the number of post-operative empyemas (1%) was lower than that (7.5%) found in 53 comparable patients who were previously treated with placebo. In the 'placebo group', empyema was due to gram-positive bacteria, while in the 'prophylaxis group', it was caused by Gram-negative bacteria (Pseudomonas aeruginosa). A significant (P < 0.05) correlation between infected bronchial secretions, pleural space contamination at surgery, contamination of chest fluid and drains during the post-operative period, and empyema development was demonstrated. In conclusion, antibiotic prophylaxis, while being effective in preventing post-operative empyema, may induce the colonization of the respiratory tract with highly resistant gram-negative bacteria.

Occurrence of human papillomavirus DNA in primary lung neoplasms

The occurrence of human papillomavirus (HPV) DNA in primary lung carcinomas and in squamous metaplasia of the bronchus was studied using in situ hybridization techniques and commercially available biotinylated DNA probes to HPV subtypes 6/11, 16/18, and 31/33/35. The authors found HPV DNA in six of 20 cases of squamous cell carcinoma and one of six cases of large cell undifferentiated carcinoma. There were two cases each of the 6/11 serotypes and the 16/18 serotypes and three cases of the 31/33/35 serotypes. Infected cells of the squamous carcinomas uniformly showed koilocytosis. No case of adenocarcinoma, bronchioloalveolar carcinoma, or small cell carcinoma was positive (of 32 cases). Areas of squamous metaplasia in infected tumors showed similar HPV DNA expression in 15% of cases, especially in those with condylomatous atypia. In 5.8% of random bronchial biopsies of squamous metaplasia, HPV DNA was identified. The relationship of HPV infection to the development of upper and lower respiratory tract carcinomas is discussed.