Frequencies and expression levels of programmed death ligand 1 (PD-L1) in circulating tumor RNA (ctRNA) in various cancer types

BACKGROUND

Precision medicine and prediction of therapeutic response requires monitoring potential biomarkers before and after treatment. Liquid biopsies provide noninvasive prognostic markers such as circulating tumor DNA and RNA. Circulating tumor RNA (ctRNA) in blood is also used to identify mutations in genes of interest, but additionally, provides information about relative expression levels of important genes. In this study, we analyzed PD-L1 expression in ctRNA isolated from various cancer types. Tumors inhibit antitumor response by modulating the immune checkpoint proteins programmed death ligand 1 (PD-L1) and its cognate receptor PD1. The expression of these genes has been implicated in evasion of immune response and resistance to targeted therapies.

METHODS

Blood samples were collected from gastric (GC), colorectal (CRC), lung (NSCLC), breast (BC), prostate cancer (PC) patients, and a healthy control group. ctRNA was purified from fractionated plasma, and following reverse transcription, levels of PD-L1 expression were analyzed using qPCR.

RESULTS

PD-L1 expression was detected in the plasma ctRNA of all cancer types at varying frequencies but no PD-L1 mRNA was detected in cancer-free individuals. The frequencies of PD-L1 expression were significantly different among the various cancer types but the median relative PD-L1 expression values were not significantly different. In 12 cases where plasma and tumor tissue were available from the same patients, there was a high degree of concordance between expression of PD-L1 protein in tumor tissues and PD-L1 gene expression in plasma, and both methods were equally predictive of response to nivolumab.

CONCLUSIONS

PD-L1 mRNA can be detected and quantitated in ctRNA of cancer patients. These results pave the way for further studies aimed at determining whether monitoring the levels of PD-L1 mRNA in blood can identify patients who are most likely to benefit from the conventional treatment.

Methylation of L1RE1, RARB, and RASSF1 function as possible biomarkers for the differential diagnosis of lung cancer

Background

Lung cancer is the major cause of cancer-related deaths worldwide. Differential diagnosis can be difficult, especially when only small samples are available. Epigenetic changes are frequently tissue-specific events in carcinogenesis and hence may serve as diagnostic biomarkers.

Material and methods

138 representative formalin-fixed, paraffin-embedded (FFPE) tissues (116 lung cancer cases and 22 benign controls) were used for targeted DNA methylation analysis via pyrosequencing of ten literature-derived methylation markers (APC, CDH1, CDKN2A, EFEMP1, FHIT, L1RE1, MGMT, PTEN, RARB, and RASSF1). Methylation levels were analyzed with the Classification and Regression Tree Algorithm (CART), Conditional Interference Trees (ctree) and ROC. Validation was performed with additional 27 lung cancer cases and 38 benign controls. TCGA data for 282 lung cancer cases was included in the analysis.

Results

CART and ctree analysis identified the combination of L1RE1 and RARB as well as L1RE1 and RASSF1 as independent methylation markers with high discriminative power between tumor and benign tissue (for each combination, 91% specificity and 100% sensitivity). L1RE1 methylation associated significantly with tumor type and grade (p<0.001) with highest methylation in the control group. The opposite was found for RARB (p<0.001). RASSF1 methylation increased with tumor type and grade (p<0.001) with strongest methylation in neuroendocrine tumors (NET).

Conclusion

Hypomethylation of L1RE1 is frequent in tumors compared to benign controls and associates with higher grade, whereas increasing methylation of RARB is an independent marker for tumors and higher grade. RASSF1 hypermethylation was frequent in tumors and most prominent in NET making it an auxiliary marker for separation of NSCLC and NET. L1RE1 in combination with either RARB or RASSF1 could function as biomarkers for separating lung cancer and non-cancerous tissue and could be useful for samples of limited size such as biopsies.

Growth patterns of pulmonary metastases: should we adjust resection techniques to primary histology and size?

OBJECTIVES

Safety margins in pulmonary metastasectomy are not yet well defined. We hypothesize that histological subtype, size of the lesion and local growth characteristics must be taken into consideration during metastasectomy. This study was conducted to examine and classify growth patterns at resection margins and define the relationships between aggressive local growth, metastasis size and local recurrence to direct metastasectomy.

METHODS

Histologic sections of pulmonary metastases were prospectively collected and haematoxylin-eosin stains were systematically evaluated and classified by their pattern of lung tissue infiltration. Logistic regression was used to model the association between the subgroups of colorectal, renal cell and epithelial cancers and melanomas and sarcomas.

RESULTS

From 183 patients, 412 lung specimens were removed, which contained 459 pulmonary metastases. We found that 58% of all lesions had microscopic signs of aggressive local dissemination. The metastases showed histology-specific patterns of local growth: sarcoma was associated with pleural infiltration; colorectal metastases with interstitial spread and aerogenous spread of floating cancer cell clusters; and melanoma with perivascular growth and with lymph vessel involvement. Aggressive patterns of growth had an increasing probability of around 3% for each additional millimetre of metastasis diameter. Local intrapulmonary recurrence was significantly more common in association with interstitial growth and pleural penetration as well as safety margins <7 mm.

CONCLUSIONS

Approximately 40% of all lung metastases have a smooth surface and might be resected with small margins. Growth characteristics within the lung differ with the histologic subtype and safety margins should generally increase with the size of the metastasis.

Effectiveness of Robotic Lobectomy-Outcome and Learning Curve in a High Volume Center

BACKGROUND

 Robotic surgery has been developed as a sophisticated tool to expand possibilities in minimal invasive surgery. The learning curve for this method is short in various surgical fields; however, limited data exist on the learning curve in robotic thoracic surgery.

METHODS

 This study analyzes a single center experience of robotic lobectomies using a prospectively kept database. Perioperative data and outcome of patients during the learning curve were compared with patients operated with increased institutional experience. The learning curve was defined as the initial 20 lobectomies.

RESULTS

 Sixty-four robotic lobectomies were performed between January 2014 and February 2017. Indications, preoperative lung functions, comorbidities, patient age, and tumor stage were comparable between patients operated during the learning curve and thereafter. The mean operative time could be significantly reduced after the learning curve (286 ± 86 vs. 211 ± 62 minutes; p = 0.0003). The conversion rate dropped from 4 of 20 (20%) during the learning curve to 2 of 44 (4.5%, p = 0.07) thereafter. Chest tube duration (4.3 ± 2.9 vs. 3.8 ± 2.1 days) and hospital stay (8.3 ± 3.4 vs. 7.9 ± 4.5 days) were not different in the two phases. The number of resected lymph nodes increased from 11.2 ± 6.8 to 13.9 ± 6.5 (p = 0.0797). Lymph node upstaging was achieved in 8 (12.9%) cases. Ninety-day mortality was 0%, and 2-year overall survival was 83%.

CONCLUSIONS

 Robotic thoracic surgery can be safely performed and trained with low complication rates and contributes to the extension of minimal invasive thoracic surgery. The initial learning curve in our experience is overcome after 20 cases. However, to become proficient in more advanced procedures and to further reduce operative time, additional training is required. Prospective studies are required to clearly determine the role of robotic surgery in comparison to the video-assisted thoracoscopic surgery (VATS) procedures.

Prognostic value of MIB-1 proliferation index in solitary fibrous tumors of the pleura implemented in a new score - a multicenter study

Background

Although the majority of solitary fibrous tumors of the pleura (SFTP) follow a benign course, 10–25% of patients suffer from recurrence or metastatic disease. Several scoring models have been proposed to predict the outcome. However, none of these included immunohistochemical (IHC) markers as possible prognosticators.

Methods

In this multicenter study, we collected clinical data and formalin-fixed and paraffin-embedded (FFPE) tissue blocks of patients with histologically proven SFTP which had been surgically resected between 2000 und 2015. After systematic and extensive IHC staining on tissue microarrays, the results were analyzed and compared to histomorphological and clinical data for their possible prognostic value.

Results

In total, 78 patients (mean age 61 ± 11 years) were included. Of these, 9 patients (11%) had an adverse outcome including SFTP recurrence (n = 6) or SFTP-related death (n = 3). Mean overall survival was 172 ± 13 months. 1 and 10-year event-free survival rates were 99% and 93%. In the multivariable analysis only MIB-1 proliferation index (Ki-67) ≥10% (HR 12.3, CI 1.1–139.5, p = 0.043), ≥4 mitoses per 10 high power fields (HR 36.5, CI 1.2–1103.7, p = 0.039) and tumor size larger than 10 cm (HR 81.8, CI 1.7–4016.8, p = 0.027) were independently associated with adverse outcome.

Conclusion

A high proliferation rate by MIB-1 IHC was associated with impaired outcome. Upon this, we established a new score using mitosis, necrosis, size of the tumor and MIB-1, which performed better than the traditional scores in our data set. This prognostic score could help to better evaluate outcome of SFTP, but requires external validation.

Pulmonary metastasectomy for sarcoma-Essen experience

Background

Pulmonary metastasectomy is an established treatment modality for patients with soft as well as bone tissue sarcomas. Aim of this study is to describe the Essen experience in the surgical management of patients with pulmonary sarcoma metastases.

Methods

This is a retrospective single center analysis of perioperative outcome of patients undergoing pulmonary metastasectomy for sarcoma metastases from 1997-2017 and a summary of published papers on this topic.

Results

During the observation period 327 patients (49.23% female) underwent pulmonary metastasectomy for metastases of extrathoracic sarcomas in curative intent. The number of resected metastases was 1-3 in 283 cases (86.54%), 4-9 in 31 cases (9.48%) and 10 or more lesions in 14 cases (4.28%). Wedge resections or precision excisions with laser or electrocautery were performed in 278 cases (85.02%), anatomical segmental resections in 16 patients (4.89%) and lobectomies in 33 patients (10.09%). Bilateral procedures were performed in 98 cases (29.96%). Lymphadenectomy was performed in 122 patients. Positive lymph nodes were found only in 6 cases. All of these cases were patients with soft tissue sarcoma as primary tumor. Preoperative neoadjuvant treatment was performed in 79 patients (24.15%) with chemotherapy, in 54 patients (16.51%) with radiochemotherapy and in 10 patients (3.05%) with radiotherapy. Major postoperative complications were observed in 2.75% of all patients. Thirty-day mortality was 0%.

Conclusions

Pulmonary metastasectomy in sarcoma patients is a feasible and safe treatment strategy even in patients with bilateral metastases and multiple lesions. Thoracic lymph node metastases are rare and did not influence survival in our cohort.

Quantitative Analysis of Proteome Modulations in Alveolar Epithelial Type II Cells in Response to Pulmonary Aspergillus fumigatus Infection

The ubiquitous mold Aspergillus fumigatus threatens immunosuppressed patients as inducer of lethal invasive aspergillosis. A. fumigatus conidia are airborne and reach the alveoli, where they encounter alveolar epithelial cells (AEC). Previous studies reported the importance of the surfactant-producing AEC II during A. fumigatus infection via in vitro experiments using cell lines. We established a negative isolation protocol yielding untouched primary murine AEC II with a purity >90%, allowing ex vivo analyses of the cells, which encountered the mold in vivo By label-free proteome analysis of AEC II isolated from mice 24h after A. fumigatus or mock infection we quantified 2256 proteins and found 154 proteins to be significantly differentially abundant between both groups (ANOVA p value ≤ 0.01, ratio of means ≥1.5 or ≤0.67, quantified with ≥2 peptides). Most of these proteins were higher abundant in the infected condition and reflected a comprehensive activation of AEC II on interaction with A. fumigatus This was especially represented by proteins related to oxidative phosphorylation, hence energy production. However, the most strongly induced protein was the l-amino acid oxidase (LAAO) Interleukin 4 induced 1 (IL4I1) with a 42.9 fold higher abundance (ANOVA p value 2.91^-10). IL4I1 has previously been found in B cells, macrophages, dendritic cells and rare neurons. Increased IL4I1 abundance in AEC II was confirmed by qPCR, Western blot and immunohistology. Furthermore, A. fumigatus infected lungs showed high levels of IL4I1 metabolic products. Importantly, higher IL4I1 abundance was also confirmed in lung tissue from human aspergilloma. Because LAAO are key enzymes for bactericidal product generation, AEC II might actively participate in pathogen defense. We provide insights into proteome changes of primary AEC II thereby opening new avenues to analyze the molecular changes of this central lung cell on infectious threats. Data are available via ProteomeXchange with identifier PXD005834.

Idiopathic pleuroparenchymal fibroelastosis (PPFE) - A case study of a rare entity

Idiopathic pleuroparenchymal fibroelastosis (IPPFE) was recognized as a rare new entity. We report the case of a 63 years old female suffering from progressive dyspnea and dry cough for three years. Two years before admission to our hospital, idiopathic pulmonary fibrosis (IPF) was diagnosed in another hospital and treatment with prednisolone and N-acetylcysteine (NAC) was commenced. At admission HRCT showed upper lobe dominant fibrosis and associated pleural thickening. Surgical biopsies were re-evaluated and revealed fibroelastosis with pleural thickening and a probable UIP pattern, consistent with idiopathic PPFE. Treatment with pirfenidone was initiated due to progression under prednisolone and NAC. Upper lobe predominant pleural thickening with associated subpleural fibrotic changes should raise suspicion of PPFE.

Erroneous diagnosis of small cell lung cancer based on small biopsies with far-reaching consequences: case report of a typical carcinoid tumor

Although neuroendocrine tumors (NETs) of the lung are frequently discussed together, carcinoids are very different from high-grade small cell lung carcinoma (SCLC). SCLC is found in heavy-smoking, older patients, whereas smoking is not strongly associated with carcinoid tumors. We present the case of a 46-year-old never smoking woman who was misdiagnosed with SCLC. The patient was not responsive to radio-chemotherapy plus prophylactic cranial irradiation (PCI); she had a typical carcinoid (TC) tumor according to the final pathology report. We aim to demonstrate that diagnosis of SCLC based on cytology or small biopsy specimens must be scrutinized when the clinical constellation is unusual, or when the follow-up assessment shows no response to systemic treatment.

High Prevalence of Concomitant Oncogene Mutations in Prospectively Identified Patients with ROS1-Positive Metastatic Lung Cancer

OBJECTIVES

Chromosomal rearrangements involving ROS1 define a rare entity of lung adenocarcinomas with exquisite sensitivity to molecularly targeted therapy. We report clinical outcomes and genomic findings of patients with ROS1-positive lung cancer who were prospectively identified within a multiplex biomarker profiling program at the West German Cancer Center.

METHODS

Standardized immunohistochemical (IHC) analysis, fluorescence in situ hybridization (FISH), and hotspot mutation analyses were performed in 1345 patients with advanced cancer, including 805 patients with metastatic lung adenocarcinoma. Clinical and epidemiological data were retrieved from the institutional database.

RESULTS

ROS1 positivity by IHC analysis was detected in 25 patients with lung cancer (4.8% of lung adenocarcinomas), including 13 patients (2.5%) with ROS1 FISH positivity with a cutoff of at least 15% of events. Of the ROS1 IHC analysis-positive cases, 36% presented with concomitant oncogenic driver mutations involving EGFR (six cases, five of which were clinically validated by response to EGFR-targeting agents), KRAS (two cases), phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha gene (PIK3CA), and BRAF. Three cases initially classified as ROS1 FISH-negative passed the threshold of 15% positive events when repeat biopsies were analyzed at progression. The median overall survival of the ROS1-positive patients (104 months) was significantly superior to that of the 261 patients with EGFR/anaplastic lymphoma kinase/ROS1-negative lung adenocarcinoma (24.4 months, p = 0.044). Interestingly, the overall survival of the 13 ROS1-positive patients with lung cancer from initiation of pemetrexed-based chemotherapy was significantly prolonged when compared with that of 169 pemetrexed-treated patients with EGFR/anaplastic lymphoma kinase/ROS1-negative adenocarcinoma (p = 0.01).

CONCLUSIONS

ROS1-positive metastatic lung adenocarcinomas frequently harbor concomitant oncogenic driver mutations. Levels of ROS1 FISH-positive events are variable over time. This heterogeneity provides additional therapeutic options if discovered by multiplex biomarker testing and repeat biopsies.