Elastosis in lung carcinoma: immunohistochemical, ultrastructural and clinical studies

Machine-Learning-Based Classification Model to Address Diagnostic Challenges in Transbronchial Lung Biopsy

BACKGROUND

When obtaining specimens from pulmonary nodules in TBLB, distinguishing between benign samples and mis-sampling from a tumor presents a challenge. Our objective is to develop a machine-learning-based classifier for TBLB specimens.

METHODS

Three pathologists assessed six pathological findings, including interface bronchitis/bronchiolitis (IB/B), plasma cell infiltration (PLC), eosinophil infiltration (Eo), lymphoid aggregation (Ly), fibroelastosis (FE), and organizing pneumonia (OP), as potential histologic markers to distinguish between benign and malignant conditions. A total of 251 TBLB cases with defined benign and malignant outcomes based on clinical follow-up were collected and a gradient-boosted decision-tree-based machine learning model (XGBoost) was trained and tested on randomly split training and test sets.

RESULTS

Five pathological changes showed independent, mild-to-moderate associations (AUC ranging from 0.58 to 0.75) with benign conditions, with IB/B being the strongest predictor. On the other hand, FE emerged to be the sole indicator of malignant conditions with a mild association (AUC = 0.66). Our model was trained on 200 cases and tested on 51 cases, achieving an AUC of 0.78 for the binary classification of benign vs. malignant on the test set.

CONCLUSION

The machine-learning model developed has the potential to distinguish between benign and malignant conditions in TBLB samples excluding the presence or absence of tumor cells, thereby improving diagnostic accuracy and reducing the burden of repeated sampling procedures for patients.

The efficacy of a machine learning algorithm for assessing tumour components as a prognostic marker of surgically resected stage IA lung adenocarcinoma

BACKGROUND

The importance of the stromal components in tumour progression has been discussed widely, but their prognostic role in small size tumours with lepidic components is not fully understood. Applying digital tissue image analysis to whole-slide imaging may enhance the accuracy and reproducibility of pathological assessment. This study aimed to evaluate the prognostic value of tumour components of lung adenocarcinoma by measuring the dimensions of the tumour consisting elements separately, using a machine learning algorithm.

METHODS

Between September 2002 and December 2016, 317 patients with surgically resected, pathological stage IA adenocarcinoma with lepidic components were analysed. We assessed the whole tumour area, including the lepidic components, and measured the epithelium, collagen, elastin areas and alveolar air space. We analysed the prognostic impact of each tumour component.

RESULTS

The dimensions of the epithelium and collagen areas were independent significant risk factors for recurrence-free survival (hazard ratio, 8.38; 95% confidence interval, 1.14-61.88; P = 0.037, and hazard ratio, 2.58; 95% confidence interval, 1.14-5.83; P = 0.022, respectively). According to the subgroup analysis when combining the epithelium and collagen areas as risk factors, patients with tumours consisting of both large epithelium and collagen areas showed significantly poor prognoses (P = 0.002).

CONCLUSIONS

We assessed tumour components using a machine learning algorithm to stratify the post-operative prognosis of surgically resected stage IA adenocarcinomas. This method might guide the selection of patients with a high risk of recurrence.

Usual interstitial pneumonia: a review of the pathogenesis and discussion of elastin fibres, type II pneumocytes and proposed roles in the pathogenesis

The pathogenesis of idiopathic pulmonary fibrosis (IPF) and its histological counterpart, usual interstitial pneumonia (UIP) remains debated. IPF/UIP is a disease characterised by respiratory restriction, and while there have been recent advances in treatment, mortality remains high. Genetic and environmental factors predispose to its development and aberrant alveolar repair is thought to be central. Following alveolar injury, the type II pneumocyte (AEC2) replaces the damaged thin type I pneumocytes. Despite the interstitial fibroblast being considered instrumental in formation of the fibrosis, there has been little consideration for a role for AEC2 in the repair of the septal interstitium. Elastin is a complex protein that conveys flexibility and recoil to the lung. The fibroblast is presumed to produce elastin but there is evidence that the AEC2 may have a role in production or deposition. While the lung is an elastic organ, the role of elastin in repair of lung injury and its possible role in UIP has not been explored in depth. In this paper, pathogenetic mechanisms of UIP involving AEC2 and elastin are reviewed and the possible role of AEC2 in elastin generation is proposed.

Elastin in pulmonary pathology: relevance in tumors with lepidic or papillary appearance. A comprehensive understanding from a morphological viewpoint

Elastin and collagen are the main components of the lung connective tissue network, and together provide the lung with elasticity and tensile strength. In pulmonary pathology, elastin staining is used to variable extents in different countries. These uses include evaluation of the pleura in staging, and the distinction of invasion from collapse of alveoli after surgery (iatrogenic collapse). In the latter, elastin staining is used to highlight distorted but pre‐existing alveolar architecture from true invasion. In addition to variable levels of use and experience, the interpretation of elastin staining in some adenocarcinomas leads to interpretative differences between collapsed lepidic patterns and true papillary patterns. This review aims to summarise the existing data on the use of elastin staining in pulmonary pathology, on the basis of literature data and morphological characteristics. The effect of iatrogenic collapse and the interpretation of elastin staining in pulmonary adenocarcinomas is discussed in detail, especially for the distinction between lepidic patterns and papillary carcinoma.

Alveolar Epithelial Denudation Is a Major Factor in the Pathogenesis of Pleuroparenchymal Fibroelastosis

The pathogenesis of pleuroparenchymal fibroelastosis (PPFE), a rare interstitial lung disease, remains unclear. Based on previous reports and our experience, we hypothesized that alveolar epithelial denudation (AED) was involved in the pathogenesis of PPFE. This multicenter retrospective study investigated the percentage of AED and the features of the denudated areas in 26 PPFE cases, 30 idiopathic pulmonary fibrosis (IPF) cases, and 29 controls. PPFE patients had lower forced vital capacities and higher residual volume/total lung capacities in pulmonary function tests compared to IPF and control patients. Histopathologically, subpleural fibroelastosis was observed in PPFE, and AED was observed in 12.01% of cases in the subpleural or interlobular septa regardless of fibroelastosis. The percentage of AED in the PPFE group was significantly higher than that in the IPF group (6.84%; p = 0.03) and the normal group (1.19%; p < 0.001). In the IPF group, the percentage of AED and the presence of PPFE-like lesions in the upper lobes were examined radiologically, but no correlation was found. We showed that AED frequently occurred in PPFE. AED was less frequent in IPF, which, in combination with imaging data, suggests that PPFE may have a different pathogenesis from IPF.

Elastin in the Tumor Microenvironment

Elastic fibers are found in the extracellular matrix (ECM) of tissues requiring resilience and depend on elasticity. Elastin and its degradation products have multiple roles in the oncologic process. In many malignancies, the remodeled ECM expresses high levels of the elastin protein which may have either positive or negative effects on tumor growth. Elastin cross-linking with other ECM components and the enzymes governing this process all have effects on tumorigenesis. Elastases, and specifically neutrophil elastase, are key drivers of invasion and metastasis and therefore are important targets for inhibition. Elastin degradation leads to the generation of bioactive fragments and elastin-derived peptides that further modulate tumor growth and spread. Interestingly, elastin-like peptides (ELP) and elastin-derived peptides (EDP) may also be utilized as nano-carriers to combat tumor growth. EDPs drive tumor development in a variety of ways, and specifically targeting EDPs and their binding proteins are major objectives for ongoing and future anti-cancer therapies. Research on both the direct anti-cancer activity and the drug delivery capabilities of ELPs is another area likely to result in novel therapeutic agents in the near future.

Ki-67, TGF-β1, and elastin content are significantly altered in lip carcinogenesis

Epithelial changes observed in actinic cheilitis (AC) and lower lip squamous cell carcinoma (LLSCC) have been studied using different markers in order to observe diagnostic and prognostic factors for both lesions. The aim of the present study was to analyze Ki-67, TGF-β1, and elastin content in AC and LLSCC to determine the possible role of these proteins in lip carcinogenesis. Medical records of 29 cases of AC and 53 cases of LLSCC were analyzed. Lesions were classified according histological pattern and submitted to immunostaining for Ki-67, TGF-β1, and elastin. Different percentages of Ki-67-positive cells were found in AC depending on the degree of epithelial dysplasia (p < 0.01). An association was also found between the percentage of Ki-67-positive cells and tumor grade in LLSCC (p < 0.01). An inverse correlation was found between Ki-67 and TGF-β1 in AC and LLSCC (p < 0.01). Elastosis was thinner and more discontinuous in LLSCC in comparison to AC, and this difference in the elastin immunolabeling pattern was statistically significant between groups (p < 0.01). The present findings indicate that changes in Ki-67 and TGF-β1 content contribute to lip carcinogenesis. Furthermore, elastin content reflects changes in the extracellular matrix in both AC and LLSCC.

Prognostic impact of nm23-H1 and PCNA expression in pathologic stage I non-small cell lung cancer

INTRODUCTION

The purpose of this study was to evaluate the value of nm23-H1 and proliferating cell nuclear antigen (PCNA) expression as well as other confirmed prognostic factors in predicting the clinical outcome after definitive surgery of pathologic stage I non-small cell lung cancer (NSCLC).

METHODS

Four hundred fifty-two consecutive and non-selected patients who underwent definitive surgery for stage I NSCLC were included in this study. Formalin-fixed paraffin-embedded specimens were stained for nm23-H1 and PCNA, the correlation between the staining and its clinicopathological parameters, and its prognostic power were analyzed statistically.

RESULTS

Of the 452 patients studied, 320 cases (70.8%) were high expression for nm23-H1. A total of 182 carcinomas (40.3%) were PCNA high expression tumors. PCNA expression correlated with serum CEA level (P < 0.001), and differentiation (P < 0.001). In univariate analysis by log-rank test, serum CEA level, pT stage, differentiation, nm23-H1 expression, and PCNA expression were significant prognostic factors (P = 0.037, 0.021, <0.001, 0.042, and 0.014, respectively). In multivariate analysis, pT stage and nm23-H1 expression maintained its independent prognostic influence on overall survival (P = 0.041 and 0.003, respectively).

CONCLUSIONS

nm23-H1 may be a good biomarker to be applied in clinic to predict the prognosis of patients with completely resected pathologic stage I NSCLC.

Elastic fiber staining and cytokeratin 15 expression pattern in trichoepithelioma and basal cell carcinoma

Trichoepithelioma (TE) is a benign neoplasm of the skin that resembles basal cell carcinoma (BCC) in its clinical and histological features. In this study, we evaluate the usefulness of elastic fiber staining and cytokeratin 15 expression pattern in terms of distinguishing TE from BCC. Eleven TE and 17 BCC were examined histochemically and immunohistochemically. It was found that BCC contain more elastic fiber than TE, and that more TE show peripheral localization than BCC in cytokeratin 15 expression patterns. The present study shows that elastic fiber staining and cytokeratin 15 expression pattern may aid the differentiation of TE from BCC.

Visceral pleural invasion is an invasive and aggressive indicator of non-small cell lung cancer

OBJECTIVE

Although visceral pleural invasion by non-small cell lung cancer is considered a poor-prognostic factor, further information is lacking, especially in relation to other clinicopathologic prognostic factors. We assessed the relationship between visceral pleural invasion and other clinicopathologic characteristics and evaluated its significance as a prognostic factor.

METHODS

We reviewed 1074 patients with surgically resected T1/2 non-small cell lung cancer for their clinicopathologic characteristics and prognoses. The patients were divided into 2 groups according to visceral pleural invasion status (visceral pleural invasion group and non-visceral pleural invasion group). Both groups were compared with regard to age, sex, histology, tumor size, tumor differentiation, lymph node involvement, lymphatic invasion, vascular invasion, scar grade, nuclear atypia, mitotic index, serum carcinoembryonic antigen level, and survival. Univariate and multivariate analyses were conducted.

RESULTS

Visceral pleural invasion was identified in 288 (26.8%) of the resected specimens. Survival was 76.0% at 5 years and 53.2% at 10 years in the non-visceral pleural invasion group and was 49.8% at 5 years and 37.0% at 10 years in the visceral pleural invasion group. The difference between groups was highly significant ( P < .0001). Visceral pleural invasion was also significantly associated with a higher frequency of lymph node involvement. However, regardless of N status (N0 or N1/2), there was a significant difference in survival when the visceral pleura was invaded. Visceral pleural invasion was observed significantly more frequently in tumors with factors indicative of tumor aggressiveness/invasiveness: moderate/poor differentiation, lymphatic invasion, vascular invasion, high scar grade, high nuclear atypia grade, high mitotic index, and high serum carcinoembryonic antigen level. By multivariate analysis, visceral pleural invasion proved to be a significant independent predictor of poor prognosis in non-small-cell lung cancer patients with or without lymph node involvement.

CONCLUSIONS

Visceral pleural invasion is a significant poor-prognostic factor, regardless of N status. Our analyses indicated that visceral pleural invasion is an independent indicator of non-small cell lung cancer invasiveness and aggressiveness.

Stromal elastosis in papillary thyroid carcinomas

Stromal elastosis, defined as dense aggregations of elastic fibers, is found in some neoplastic tissues especially in malignant tumors of the breast and lung. Although also found in thyroid tissue, stromal elastosis in thyroid neoplasms have received little attention. To clarify the histopathological significance of stromal elastosis in the thyroid, we examined neoplastic (n = 223) and hyperplastic (n = 82) thyroid tissues in conjunction with cancer tissues (n = 193) of various other organs. Stromal elastosis was observed as deposits of pale homogeneous material in hematoxylin and eosin stain, and distinctively highlighted by elastic-van Gieson's stain. On immunohistochemical examination, elastin and tropoelastin were confirmed in these deposits. Stromal elastosis was found in 66% of papillary thyroid carcinomas (PTCs), although it was not identified in other histological types of thyroid neoplasms. In PTCs, deposits of elastic fibers varied in size and shape, and were more frequently distributed in the periphery of the tumor tissue. The histological subtypes of PTC varied in prevalence of elastosis with the follicular variant's (9%) prevalence being significantly lower than that of the classical type (72%). The frequency of stromal elastosis in PTCs was very similar to the frequencies in breast and lung adenocarcinomas, and higher than the frequencies in carcinomas of other organs. In conclusion, our results suggest that stromal elastosis is a characteristic histological finding of PTCs, presumably associated with their growth pattern and/or histological architecture. It is, therefore, reasonable to propose that stromal elastosis is an ancillary feature in the histopathological diagnosis of PTCs.

Distribution of elastic fiber in tissues of normal stomach, stomach ulcer and stomach carcinoma

AIM: To study the distribution of elastic fiber (EF) in tissues of normal stomach, gastric ulcer and gastric carcinoma.

METHODS: Tissue samples, including 40 cases of stomach carcinoma, 17 cases of normal stomach and 7 cases of stomach ulcer, were studied using hematoxylin and eosin (HE) staining and EF staining. The distributions of EF were analyzed under light microscope.

RESULTS: In tissues of stomach ulcer, EF, with a deep staining, was mainly located in the muscularis mucosa adjacent to the ulcer lesion. No EF was observed in carcinoma zone, but a great amount was found in the smooth muscle and connective tissue around the lesion. EF was increased significantly in stomach carcinoma specimens, compared with that in normal tissues (P = 0.0042). Hyperplasia of small vessel endothelia was observed in cancer tissues but not in ulcer tissues.

CONCLUSION: The distribution patterns of EF are different in normal stomach, gastric ulcer and gastric carcinoma. The increase of EF in gastric ulcer may be related to the stimulation of chronic inflammation; while in carcinoma, in addition to the chronic inflammatory stimulation, the EF increase in the surrounding tissues may also result from augmented EF production triggered by the cancer cells indirectly through releasing stimulatory factors or directly via regulating gene expression in EF-producing cells. The increase of EF in the stomach wall lesion is a chronic process.

alpha1-antitrypsin and its C-terminal fragment attenuate effects of degranulated neutrophil-conditioned medium on lung cancer HCC cells, in vitro

Background

Tumor microenvironment, which is largely affected by inflammatory cells, is a crucial participant in the neoplastic process through promotion of cell proliferation, survival and migration. We measured the effects of polymorphonuclear neutrophil (PMN) conditioned medium alone, and supplemented with serine proteinase inhibitor α-1 antitrypsin (AAT) or its C-terminal fragment (C-36 peptide), on cultured lung cancer cells.

Methods

Lung cancer HCC cells were grown in a regular medium or in a PMN-conditioned medium in the presence or absence of AAT (0.5 mg/ml) or its C-36 peptide (0.06 mg/ml) for 24 h. Cell proliferation, invasiveness and release of IL-8 and VEGF were analyzed by [³H]-thymidine incorporation, Matrigel invasion and ELISA methods, respectively.

Results

Cells exposed to PMN-conditioned medium show decreased proliferation and IL-8 release by 3.9-fold, p < 0.001 and 1.3-fold, p < 0.05, respectively, and increased invasiveness by 2-fold (p < 0.001) compared to non-treated controls. In the presence of AAT, PMN-conditioned medium loses its effects on cell proliferation, invasiveness and IL-8 release, whereas VEGF is up-regulated by 3.7-fold (p < 0.001) compared to controls. Similarly, C-36 peptide abolishes the effects of PMN-conditioned medium on cell invasiveness, but does not alter its effects on cell proliferation, IL-8 and VEGF release. Direct HCC cell exposure to AAT enhances VEGF, but inhibits IL-8 release by 1.7-fold (p < 0.001) and 1.4-fold (p < 0.01) respectively, and reduces proliferation 2.5-fold (p < 0.01). In contrast, C-36 peptide alone did not affect these parameters, but inhibited cell invasiveness by 51.4% (p < 0.001), when compared with non-treated controls.

Conclusions

Our data provide evidence that neutrophil derived factors decrease lung cancer HCC cell proliferation and IL-8 release, but increase cell invasiveness. These effects were found to be modulated by exogenously present serine proteinase inhibitor, AAT, and its C-terminal fragment, which points to a complexity of the relationships between tumor cell biological activities and local microenvironment.

Multiple effects of alpha1-antitrypsin on breast carcinoma MDA-MB 468 cell growth and invasiveness

The degradation of extracellular matrix during cancer invasion results from the action of several protease and protease inhibitor systems. Alpha(1)-Antitrypsin (AAT) is a serine proteinase inhibitor produced by various tumour cells, and its plasma concentration rises during inflammation, infection and malignant diseases. AAT is found in a native, inhibitory active form, but also in other, non-inhibitory forms including cleaved and/or degraded. To test a hypothesis that AAT dependent on its molecular form may have multiple effects on tumour cell behaviour, breast cancer cells, MDA-MB 468, were cultured alone or stimulated with a native AAT or its C-terminal fragment (C-36) at a concentration of 5 micromol/l for 2, 24 and 48 hours. Native AAT added to the cells for 2 hours enhanced transforming growth factor beta 1 (TGFbeta1) levels by 50%, but inhibited cell proliferation (by 61%), reduced interleukin 6 (IL-6) levels (by 87%) and activity (by about 66%), compared with non-stimulated cells. Native AAT showed similar, but less pronounced, effects when added to the cells for 24 and 48 hours. Under the same experimental conditions the cells exposed to the C-36 peptide significantly increased in proliferation, invasiveness and showed higher IL-6 levels. In addition, cells treated with the C-36 for 48 hours increased in NFkappaB (nuclear factor kappa B) activity. These results indicate that AAT, dependent on its molecular form, can both suppress and induce breast tumour cell biological activity in vitro.

Modified scar grade: a prognostic indicator in small peripheral lung adenocarcinoma

BACKGROUND

Several studies have shown the prognostic value of desmoplasia for lung adenocarcinomas. The authors evaluated the density and extent of desmoplasia by modifying the scar grade, as well as the prognostic impact on patient survival.

METHODS

Modified scar grade was defined as follows: Grade 1, no desmoplasia; Grade 2, sparse desmoplastic reaction; Grade 3, dense desmoplastic reaction with diameter of 10 mm or less; Grade 4, dense desmoplastic reaction with diameter exceeding 10 mm. In addition, the prognostic impact of conventional histologic factors and modified scar grade was analyzed in 239 cases of small peripheral lung adenocarcinoma (maximum dimension, </= 30 mm) for which long-term follow-up data were available.

RESULTS

The 5 and 10-year survival rates according to the modified scar grade were 100% and 100% for Grade 1 lung adenocarcinoma (n = 29); 91.7% and 83.7% for Grade 2 (n = 61); 67.6% and 52.7% for Grade 3 (n = 78); and 50.0% and 37.5% for Grade 4 (n = 71), respectively. A significant difference in patient survival was found between Grade 1 or 2 versus Grade 3 or 4 (P < 0.0001, by log rank test). Multivariate analysis showed that modified scar grade was an independent prognostic factor (P = 0.0176), as were pathologic stage (P = 0.0293), lymph node metastasis (P = 0.0191), lymphatic permeation (P = 0.0022), and pleural involvement (P = 0.0452). Modified scar grade also had a significant impact on survival in various subsets of patients, including those with pathologic Stage IA disease, patients with tumors of diameter 20 mm or less, or patients with mixed subtype tumors with a bronchioloalveolar component.

CONCLUSIONS

Modified scar grade is a useful prognostic factor in patients with small lung adenocarcinomas. Tumors with a sparse fibroblastic reaction (modified scar Grade 2) may represent early invasive cancers or invasive cancers with low malignant potential, which should be distinguished from frankly invasive cancers (modified scar Grade 3 or 4).