Subepithelial myofibroblast in lung adenocarcinoma: a histological indicator of excellent prognosis

Genetic and phenotypic determinants of morphologies in 3D cultures and xenografts of lung tumor cell lines

We previously proposed the classification of lung adenocarcinoma into two groups: the bronchial epithelial phenotype (BE phenotype) with high-level expressions of bronchial epithelial markers and actionable genetic abnormalities of tyrosine kinase receptors and the non-BE phenotype with low-level expressions of bronchial Bronchial epithelial (BE) epithelial markers and no actionable genetic abnormalities of tyrosine kinase receptors. Here, we performed a comprehensive analysis of tumor morphologies in 3D cultures and xenografts across a panel of lung cancer cell lines. First, we demonstrated that 40 lung cancer cell lines (23 BE and 17 non-BE) can be classified into three groups based on morphologies in 3D cultures on Matrigel: round (n = 31), stellate (n = 5), and grape-like (n = 4). The latter two morphologies were significantly frequent in the non-BE phenotype (1/23 BE, 8/17 non-BE, p = 0.0014), and the stellate morphology was only found in the non-BE phenotype. SMARCA4 mutations were significantly frequent in stellate-shaped cells (4/4 stellate, 4/34 non-stellate, p = 0.0001). Next, from the 40 cell lines, we successfully established 28 xenograft tumors (18 BE and 10 non-BE) in NOD/SCID mice and classified histological patterns of the xenograft tumors into three groups: solid (n = 20), small nests in desmoplasia (n = 4), and acinar/papillary (n = 4). The latter two patterns were characteristically found in the BE phenotype. The non-BE phenotype exhibited a solid pattern with significantly less content of alpha-SMA-positive fibroblasts (p = 0.0004) and collagen (p = 0.0006) than the BE phenotype. Thus, the morphology of the tumors in 3D cultures and xenografts, including stroma genesis, reflects the intrinsic properties of the cancer cell lines. Furthermore, this study serves as an excellent resource for lung adenocarcinoma cell lines, with clinically relevant information on molecular and morphological characteristics and drug sensitivity.

Comprehensive analysis of the prognostic and role in immune cell infiltration of MSR1 expression in lower-grade gliomas

BACKGROUND

The therapeutic effects of conventional treatment on gliomas are not promising. The tumor microenvironment (TME) has a close association with the invasiveness of multiple types of tumors, including low-grade gliomas (LGG). This study aims to validate the prognostic and immune-related role of macrophage scavenger receptor 1 (MSR1) in LGG patients.

METHODS

Data in this study were obtained from public databases. The differential expression of MSR1 was analyzed in LGG patients with different clinicopathological characteristics. Kaplan-Meier survival analysis, a time-dependent receiver operating characteristic (ROC) curve, and Cox regression analysis were used to assess the prognostic value of MSR1. Differentially expressed genes (DEGs) were screened between the high and low expression groups of MSR1. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) were used to annotate the function of these DEGs. Hallmark gene sets were identified based on MSR1 by Gene Set Enrichment Analysis (GSEA). Difference analysis and correlation analysis were used to study the relationship between MSR1 and TME-related scores, tumor-infiltrating immune cells (TIICs), immune-related gene sets, and immune checkpoints (ICPs). The single-cell sequencing data were processed to identify the cell types expressing MSR1. The quantification of TIICs in TME was calculated by single-sample gene set enrichment analysis (ssGSEA). The differential expression of MSR1 in LGG and control brain tissues was verified by experiments.

RESULTS

There were significant differences in the expression level of MSR1 in different types of tissues and cells. MSR1 has a high prognostic value in LGG patients and can be used as an independent prognostic factor. MSR1 is closely related to TME and may play an important role in the immunotherapy of LGG patients.

CONCLUSIONS

The result of our study demonstrated that MSR1 is an independent prognostic biomarker in LGG patients and may play an important role in the TME of LGGs.

Human embryonic mesenchymal lung-conditioned medium promotes differentiation to myofibroblast and loss of stemness phenotype in lung adenocarcinoma cell lines

Background

When genes responsible for normal embryonic development are abnormally expressed in adults, it can lead to tumor development. This can suggest that the same mechanism that controls embryonic differentiation can also control tumor differentiation. We hypothesize that the malignant phenotype of lung cancer cells could acquire benign characteristics when in contact with an embryonic lung microenvironment. We cultured two lung cancer cell lines in embryonic lung mesenchyme-conditioned medium and evaluated morphological, functional and molecular changes.

Methods

The human embryonic mesenchymal lung-conditioned medium (hEML-CM) was obtained by culturing lung cells from embryos in the pseudoglandular stage of development. The NSCLC cell lines A549 and H1299 we cultured in the hEML-CM and in a tumor-conditioned medium. Morphological changes were analyzed with optical and transmission electron microscopy. To evaluate the functional effect of conditioned medium in tumor cells, we analyzed cell proliferation, migration, colony formation capacity in 2D and 3D and in vivo tumor growth capacity. The expression of the pluripotency genes OSKM, the adenocarcinoma marker NKX2-1, the lung surfactant proteins SFTP, the myofibroblast marker MYH and DNMT3A/3B was analyzed with qRT-PCR and the presence of the myofibroblast markers vimentin and α-SMA with immunofluorescence. Transcriptomic analysis was performed using Affymetrix arrays.

Results

The A549 and H1299 cells cultured in hEML-CM lost their epithelial morphology, acquired mesodermal characteristics, and decreased proliferation, migration, and colony formation capacity in 2D and 3D, as well as reduced its capacity to growth in vivo. The expression of OSKM, NKX2-1 and SFTP decreased, while that of DNMT3A/3B, vimentin, α-SMA and MYH increased. Distant matrix analysis based on transcriptomic profile showed that conditioned cells were closer to myoblast and human lung fibroblast than to normal epithelial immortalized lung cells. A total of 1631 for A549 and 866 for H1299 differentially expressed genes between control and conditioned cells were identified.

Conclusions

To the best of our knowledge, this is the first study to report that stimuli from the embryonic lung can modulate the malignant phenotype of lung cancer cells, control their growth capacity and activate their differentiation into myofibroblasts. These findings could lead to new strategies for lung cancer management.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-021-02206-z.

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.

Cancer-associated fibroblasts, matrix metalloproteinase-9 and lymphatic vessel density are associated with progression from adenocarcinoma in situ to invasive adenocarcinoma of the lung

The present study aimed to investigate the roles of cancer-associated fibroblasts (CAFs), matrix metalloproteinase-9 (MMP-9) and lymphatic vessel density (LVD) during the progression from adenocarcinoma in situ (AIS) to invasive lung adenocarcinoma (IAC). A total of 77 patients with stage 0-IA lung adenocarcinoma were enrolled. The expression levels of α-smooth muscle actin, MMP-9 and D2-40 were immunohistochemically analyzed. Survival analysis was performed using the Kaplan-Meier method. In the non-invasive component, the proportion of CAFs and the expression levels of MMP-9 increased from AIS to IAC; however, the LVD was not significantly different. CAFs were positively correlated with levels of MMP-9. The LVD had no significant correlation with CAFs and MMP-9. In the invasive component, CAFs, MMP-9 and LVD were significantly higher in IAC compared with in minimally invasive adenocarcinoma. CAFs, MMP-9 and LVD were all positively correlated with each other. The micropapillary subtype in IAC was associated with overall survival (OS). The LVD in IAC, but not MMP-9 and CAFs, was associated with OS. CAFs, MMP-9 and LVD were involved in the progression from AIS to IAC. CAFs exhibited a strong association with MMP-9 levels in the non-invasive and invasive components. The increase in the proportion of CAFs and the expression levels of MMP-9 may have been an early event before the adenocarcinoma became invasive. Once the adenocarcinoma was invasive, the LVD served an important role in tumor invasion and metastasis, and hence may be used as a prognostic marker of poor OS in stage IA IAC.

Whole-lung pathology of pleuroparenchymal fibroelastosis (PPFE) in an explanted lung: Significance of elastic fiber-rich, non-specific interstitial pneumonia-like change in chemotherapy-related PPFE

Pleuroparenchymal fibroelastosis (PPFE) is characterized by upper lobe-predominant subpleural fibroelastosis. Despite its characteristic uneven distribution, detailed whole-lung pathological features of PPFE have rarely been studied. We investigated PPFE in the explanted lungs from a 19-year-old male patient with a history of chemotherapy. Grossly, the explanted lungs showed upper lobe-predominant shrinkage with subpleural and central consolidation. Histologically, fibroelastosis was prominent in the perilobular areas and along the bronchovascular bundles. The other areas of the lung showed diffuse, non-specific interstitial pneumonia (NSIP)-like change with a characteristic increase of septal elastic fibers. In the digital image analysis, the ratio of elastic fibers to whole fibrosis (EF score) was lower in the subpleural areas than in the NSIP-like lesions, but the EF scores of the latter showed no significant difference between upper and middle/lower lobes. In the present case, the diffusely distributed elastic fiber-rich NSIP-like change, probably caused by the earlier chemotherapy, may have been conducive to the development of PPFE. This suggests that some unknown vulnerability of the upper lobe may exist, various primary lesions converging to the upper lobe predominance of PPFE.

MicroRNA-21 in cancer-associated fibroblasts supports lung adenocarcinoma progression

Cancer-associated fibroblasts (CAFs) interact closely with cancer cells, supporting their growth and invasion. To investigate the role of microRNA-21 (miR-21) in lung adenocarcinoma, and especially in its CAF component, in situ hybridisation was applied to samples from 89 invasive lung adenocarcinoma cases. MiR-21 expression was observed in both cancer cells and CAFs. When the patients were stratified by expression, miR-21 levels in CAFs (n = 9), but not in cancer cells (n = 21), were inversely correlated with patient survival; patients with miR-21^high CAFs exhibited lower survival than those with miR-21^low CAFs. The underlying mechanism was investigated in vitro. Conditioned medium (CM) from A549 lung cancer cells increased miR-21 expression in MRC-5 and IMR-90 lung fibroblasts through the transforming growth factor-β pathway, and induced CAF-like morphology and migratory capacity. MiR-21 up-regulation in lung fibroblasts induced a novel CAF-secreted protein, calumenin, as well as known CAF markers (periostin, α-smooth muscle actin, and podoplanin). Moreover, CM from the lung fibroblasts increased A549 cell proliferation in a calumenin-dependent manner. Thus, miR-21 expression in lung fibroblasts may trigger fibroblast trans-differentiation into CAFs, supporting cancer progression. Therefore, CAF miR-21 represents a pivotal prognostic marker for this scar-forming cancer of the lungs.

Tumor-Associated CD204-Positive Macrophage Is a Prognostic Marker in Clinical Stage I Lung Adenocarcinoma

Objective

Macrophages are the dominant leukocytes in the tumor microenvironment. Accumulating evidence revealed that CD204-positive (CD204+) tumor-associated macrophages (TAMs) are associated with the aggressive behavior of various cancers; however, the clinical, pathological, and prognostic associations of CD204+ TAMs with the subtype of lung adenocarcinoma have not been reported.

Methods

Tissue microarray and immunohistochemistry were constructed from clinical stage I lung adenocarcinomas with radical surgical resection. The intratumoral density of CD204+ cells was calculated using image analysis software for analyses. Survival analyses were performed using the Kaplan-Meier method and multivariate Cox proportional hazards regression models.

Results

The intratumoral density of CD204 was correlated with T stage, nodal involvement, lymphovascular invasion, and cancer relapse after the surgery, but not with age, gender, or smoking history. The density of CD204 in non-LPD was significantly higher than that in LPD. The 5-year disease-free survival (DFS) rate of CD204 high-density group was significantly worse than that of CD204 low-density group.

Conclusions

The expression of CD204 in TAMs is associated with the aggressiveness of lung adenocarcinoma. Our results suggest that a specific immune microenvironment may be associated with the biological behavior of lung adenocarcinoma.

A robust gene expression-based prognostic risk score predicts overall survival of lung adenocarcinoma patients

Identification of reliable predictive biomarkers and new therapeutic targets is a critical step for significant improvement in patient outcomes. Here, we developed a multi-step bioinformatics analytic strategy to mine large omics and clinical data to build a prognostic scoring system for predicting the overall survival (OS) of lung adenocarcinoma (LuADC) patients. In latter we first identified 1327 significantly and robustly deregulated genes, 600 of which were significantly associated with the OS of LuADC patients. Gene co-expression network analysis revealed the biological functions of these 600 genes in normal lung and LuADCs, which were found to be enriched for cell cycle-related processes, blood vessel development, cell-matrix adhesion and metabolic processes. Finally, we implemented a multiple resampling method combined with Cox regression analysis to identify a 27-gene signature associated with OS, and then created a prognostic scoring system based on this signature. This scoring system robustly predicted OS of LuADC patients in 100 sampling test sets and was further validated in four independent LuADC cohorts. In addition, in comparison to other existing prognostic gene signatures published in the literature, our signature was significantly superior in predicting OS of LuADC patients. In summary, our multi-omics and clinical data integration study created a 27-gene prognostic risk score that can predict OS of LuADC patients independent of age, gender and clinical stage. This score could guide therapeutic selection and allow stratification in clinical trials.

Drug targeting to myofibroblasts: Implications for fibrosis and cancer

Myofibroblasts are the key players in extracellular matrix remodeling, a core phenomenon in numerous devastating fibrotic diseases. Not only in organ fibrosis, but also the pivotal role of myofibroblasts in tumor progression, invasion and metastasis has recently been highlighted. Myofibroblast targeting has gained tremendous attention in order to inhibit the progression of incurable fibrotic diseases, or to limit the myofibroblast-induced tumor progression and metastasis. In this review, we outline the origin of myofibroblasts, their general characteristics and functions during fibrosis progression in three major organs: liver, kidneys and lungs as well as in cancer. We will then discuss the state-of-the art drug targeting technologies to myofibroblasts in context of the above-mentioned organs and tumor microenvironment. The overall objective of this review is therefore to advance our understanding in drug targeting to myofibroblasts, and concurrently identify opportunities and challenges for designing new strategies to develop novel diagnostics and therapeutics against fibrosis and cancer.

Lung cancer-associated myofibroblasts reveal distinctive ultrastructure and function

BACKGROUND

Cancer-associated stromal cells interact with carcinoma cells and thus participate in tumor growth. Our aim was to characterize the ultrastructure and contractile properties of stromal cells in collagen gel cultured from lung cancer of various histological types and from tumor-free lung.

METHODS

Cells cultured from lung cancer (13 adenocarcinomas, six squamous cell carcinomas, one adenosquamous carcinoma, and one pleomorphic carcinoma) and tumor-free lung were analyzed by transmission electron microscopy and three-dimensional collagen gel contraction assays. The expression of α-smooth muscle actin (α-SMA), a recognized myofibroblast marker, was examined by immunoelectron microscopy from individual cells and by Western blotting from the whole cultured cell population.

RESULTS

According to their ultrastructure, the cell lines were composed of fibroblastic and myofibroblastic cells. In electron microscopy, cells of lung cancer exhibited more myofibroblastic features displaying higher amounts of actin belts (p = 0.057) and α-SMA labeling (p = 0.010) than cells from tumor-free lung. Myofibroblasts cultured from lung cancer of smokers expressed less α-SMA labeling (p = 0.013) than counterparts from nonsmokers. Western blotting revealed that cancer-associated fibroblasts expressed more α-SMA (p = 0.006) than cells from tumor-free lung, whereas cells from tumor-free central lung of smokers showed less α-SMA (p = 0.039) than counterparts from nonsmokers. Cells cultured from cancer contracted more in collagen gel than those from tumor-free lung. The contractile capacity in collagen gel correlated with the frequency of extracellular component of fibronexus by transmission electron microscopy.

CONCLUSIONS

Lung cancer-associated myofibroblasts are different both ultrastructurally and functionally when compared with cells cultured from tumor-free lung. Smoking altered myofibroblastic phenotype, regardless of their origin.

Validation of a proliferation-based expression signature as prognostic marker in early stage lung adenocarcinoma

PURPOSE

New prognostic markers to guide treatment decisions in early stage non-small cell lung cancer are necessary to improve patient outcomes. In this report, we assess the utility of a predefined mRNA expression signature of cell-cycle progression genes (CCP score) to define 5-year risk of lung cancer-related death in patients with early stage lung adenocarcinoma.

EXPERIMENTAL DESIGN

A CCP score was calculated from the mRNA expression levels of 31 proliferation genes in stage I and stage II tumor samples from two public microarray datasets [Director's Consortium (DC) and GSE31210]. The same gene set was tested by quantitative PCR in 381 formalin-fixed paraffin-embedded (FFPE) primary tumors. Association of the CCP score with outcome was assessed by Cox proportional hazards analysis.

RESULTS

In univariate analysis, the CCP score was a strong predictor of cancer-specific survival in both the Director's Consortium cohort (P = 0.00014; HR = 2.08; 95% CI, 1.43-3.02) and GSE31210 (P = 0.0010; HR = 2.25; 95% CI, 1.42-3.56). In multivariate analysis, the CCP score remained the dominant prognostic marker in the presence of clinical variables (P = 0.0022; HR = 2.02; 95% CI, 1.29-3.17 in Director's Consortium, P = 0.0026; HR = 2.16; 95% CI, 1.32-3.53 in GSE31210). On a quantitative PCR platform, the CCP score maintained highly significant prognostic value in FFPE-derived mRNA from clinical samples in both univariate (P = 0.00033; HR = 2.10; 95% CI, 1.39-3.17) and multivariate analyses (P = 0.0071; HR = 1.92; 95% CI, 1.18-3.10).

CONCLUSIONS

The CCP score is a significant predictor of lung cancer death in early stage lung adenocarcinoma treated with surgery and may be a valuable tool in selecting patients for adjuvant treatment.

Notch and TGF-β/Smad3 pathways are involved in the interaction between cancer cells and cancer-associated fibroblasts in papillary thyroid carcinoma

Accumulating evidence suggests that cancer-associated stromal fibroblasts (CAFs) contribute to tumor growth by actively communicating with cancer cells. Our aim was to identify the signaling pathways that are involved in tumor-stromal cell interactions in human papillary thyroid carcinoma (PTC). Immunohistochemical analyses were performed with 127 archived formalin-fixed and paraffin-embedded thyroid tissue samples that included 70 cases of PTC, 35 cases of nodular goiter (NG), and 22 cases of normal thyroid tissues. The results showed that the expression levels of Notch1, transforming growth factor β (TGF-β1), and p-Smad3 in PTC cells and α-smooth muscle actin (α-SMA) in the stroma of PTC were all significantly higher than in NG and normal thyroid tissues. Further analysis showed that in PTC, higher expression levels of Notch1 and TGF-β1 were closely related with lymph node metastasis (P < 0.05), whereas for α-SMA and p-Smad3, the percent expression increased significantly with advanced tumor stages (P < 0.05). Correlation analysis revealed that TGF-β1 expression increased with increased Notch1 and p-Smad3 levels in PTC cells (P < 0.05). Moreover, a significant correlation was found between higher TGF-β1 expression in PTC cells and increased α-SMA levels in the fibroblasts surrounding the cancer cells (P < 0.05). We identified TGF-β1 as an important factor from PTC cells that act in a paracrine manner to influence the activation of stromal fibroblasts. These data suggest that the activation of Notch and TGF-β/Smad3 pathways in cancer cells influence tumor growth. Moreover, cancer cell-derived-TGF-β ligands also affect stromal cells in a paracrine fashion and enhance tumor growth.

Functional vascular smooth muscle-like cells derived from adult mouse uterine mesothelial cells

In mammalian visceral organs, vascular smooth muscle cells (VSMCs) originate from an epithelial-to-mesenchymal transition (EMT) of embryonic mesothelial cells (MCs). The ability of adult MCs to recapitulate EMT and to acquire smooth muscle (SM) markers upon provasculogenic culture suggested they might retain embryonic vasculogenic differentiation potential. However, it remains unknown whether adult MCs-derived SM-like cells may acquire specific vascular SM lineage markers and the functionality of differentiated contractile VSMCs. Here, we describe how a gentle trypsinization of adult mouse uterine cords could selectively detach their outermost uterine mesothelial layer cells. As other MCs; uterine MCs (UtMCs) uniformly expressed the epithelial markers β-catenin, ZO-1, E-cadherin, CD54, CD29, and CK18. When cultured in a modified SM differentiation media (SMDM) UtMCs initiated a loss of epithelial characteristics and gained markers expression of EMT (Twist, Snail, and Slug), stem and progenitor (Nanog, Sox2, C-kit, Gata-4, Isl-1, and nestin), SM (α-SMA, calponin, caldesmon, SM22α, desmin, SM-MHC, and smoothelin-B) and cardiac (BMP2, BMP4, ACTC1, sACTN, cTnI, cTnT, ANF, Cx43, and MLC2a). UtMCs repeatedly subcultured in SMDM acquired differentiated VSM-like characteristics and expressed smoothelin-B in the typical stress-fiber pattern expression of contractile VSMCs. Relevantly, UtMCs-derived VSM-like cells could generate "mechanical force" to compact collagen lattices and displayed in diverse degree voltage (K(+)) and receptor (endothelin-1, oxytocin, norepinephrine, carbachol and vasopressin)-induced [Ca(2+)](i) rises and contraction. Thus, we show for the first time that UtMCs could recapitulate in vitro differentiative events of early cardiovascular differentiation and transdifferentiate in cells exhibiting molecular and functional characteristics of VSMCs.

Expression and prognostic significance of MAP4K4 in lung adenocarcinoma

Accumulating evidence indicates that mitogen-activated protein 4 kinase 4 (MAP4K4) is frequently overexpressed in many types of human cancers, and plays important roles in transformation, invasiveness, adhesion, and cell migration. The aim of the present study was to explore the expression and prognostic significance of MAP4K4 in lung adenocarcinoma. The results of real-time quantitative PCR and Western blotting analysis revealed an enhanced expression of MAP4K4 in lung adenocarcinomas relative to adjacent non-tumorous lung tissues at both transcriptional and translational levels. Immunohistochemistry showed that 130 of 309 (42%) lung adenocarcinomas had high expression of MAP4K4. MAP4K4 overexpression was significantly correlated with histological grade (p=0.027), pT status (p=0.048), pN status (p=0.006), and pleural invasion (p=0.024). Patients with high MAP4K4 expression had a shorter overall survival compared with those with low MAP4K4 expression, regardless of histological grade, pT status, pN status, or pleural invasion status. Multivariate analysis identified MAP4K4 as an independent prognostic factor for lung adenocarcinoma. In conclusion, our results demonstrate that elevated MAP4K4 expression is closely associated with lung adenocarcinoma progression and has an independent prognostic value in predicting overall survival for patients with lung adenocarcinoma.

Clinicopathological characteristics of subcentimeter adenocarcinomas of the lung

BACKGROUND

Identification of subcentimeter adenocarcinoma is becoming easier due to recent advances in radiographic techniques. Pathological (p) T1a (≤20 mm) adenocarcinomas with a pure lepidic growth pattern have excellent prognosis, whereas invasive pT1a adenocarcinomas are associated with recurrence/metastasis despite their small size. Thus, an accurate pathological diagnosis is critical in such cases. This study examined the clinicopathological characteristics of subcentimeter adenocarcinomas, especially those associated with early invasive carcinomas.

METHODS

We retrospectively reviewed 595 adenocarcinomas including 66 subcentimeter carcinomas, which were then analyzed with reference to early invasive features.

RESULTS

Of the 66 subcentimeter tumors, 36 were invasive and 30 were noninvasive (adenocarcinoma in situ, AIS). Invasive carcinomas were significantly more frequent in males than females, and included 20 tumors with ≤5 mm invasion in greatest dimension (minimally invasive adenocarcinoma, MIA) and 16 tumors with >5mm invasion, 5 of which had no lepidic growth portions (entirely invasive carcinoma). Approximately half of the invasive carcinomas had no localized fibrous area ≥1 mm in diameter (LFA), and showed histological features of invasive carcinoma with localized lepidic growth including MIA (Noguchi's type C). Invasion was sometimes difficult to detect in these carcinomas. High-grade nuclear atypia was always associated with invasive carcinomas and aided the diagnosis. Moreover, invasive carcinoma with >5mm invasion was significantly associated with presence of metastasis in sensitivity analysis in patients followed for more than two years. Compared with adenocarcinomas of 11-20mm in diameter, subcentimeter carcinomas included significantly more AIS, fewer entirely invasive carcinomas, and fewer invasive carcinomas with LFA.

CONCLUSIONS

Familiarity with the histopathological characteristics of subcentimeter adenocarcinomas as described above could aid the accurate diagnosis of early invasive carcinomas.

Upregulation of cancer-associated myofibroblasts by TGF-β from scirrhous gastric carcinoma cells

BACKGROUND

Myofibroblasts in the cancer microenvironment have recently been implicated in tumour growth and metastasis of gastric cancer. However, the mechanisms responsible for the regulation of myofibroblasts in cancer-associated fibroblasts (CAFs) remain unclear. This study was performed to clarify the mechanisms for regulation of myofibroblasts in gastric cancer microenvironment.

METHODS

Two CAFs (CaF-29 and CaF-33) from the tumoural gastric wall and a normal fibroblast (NF-29) from the nontumoural gastric wall, 4 human gastric cancer cell lines from scirrhous gastric cancer (OCUM-2MD3 and OCUM-12), and non-scirrhous gastric cancer (MKN-45 and MKN-74) were used. Immunofluorescence microscopy by triple-immunofluorescence labelling (α-SMA, vimentin, and DAPI) was performed to determine the presence of α-SMA-positive myofibroblasts. Real-time RT-PCR was performed to examine α-SMA mRNA expression.

RESULTS

Immunofluorescence microscopy showed that the frequency of myofibroblasts in CaF-29 was greater than that in NF-29. The number of myofibroblasts in gastric fibroblasts gradually decreased with serial passages. Transforming growth factor-β (TGF-β) significantly increased the α-SMA expression level of CAFs. Conditioned medium from OCUM-2MD3 or OCUM-12 cells upregulated the α-SMA expression level of CAFs, but that from MKN-45 or MKN-74 cells did not. The α-SMA upregulation effect of conditioned medium from OCUM-2MD3 or OCUM-12 cells was significantly decreased by an anti-TGF-β antibody or Smad2 siRNA.

CONCLUSION

Transforming growth factor-β from scirrhous gastric carcinoma cells upregulates the number of myofibroblasts in CAFs.

Role of stromal myofibroblasts in invasive breast cancer: stromal expression of alpha-smooth muscle actin correlates with worse clinical outcome

BACKGROUND

Recently, the desmoplastic reaction has been implicated as having an important function in epithelial solid tumor biology. There have been no reports showing the relativity of invasive breast cancer and the desmoplastic reaction by a quantitative analysis of the myofibroblasts that were an important player in the desmoplastic reaction. The purpose of this study was to immunohistochemically investigate the correlation between the desmoplastic reaction and the clinicopathology of invasive breast cancer.

METHODS

The study included 60 patients with a known prognosis of invasive breast cancer. We quantified the expression of α-SMA as a marker of myofibroblasts in the invasive breast cancer. After staining samples for α-SMA, their expression was extracted and quantified as a relative percentage by computer-assisted image analysis.

RESULTS

There was relatively wide variation in the expression of α-SMA with the percentage of the area from 0.68 to 28.15% (mean 8.48 ± 5.40%). The metastasis group showed significantly higher α-SMA expression compared with the no metastasis group (p < 0.001). When the patients were divided into two groups according to their α-SMA expression using a cutoff point at the mean value of 8.48%, the high α-SMA group had a significantly poorer overall survival rate (p < 0.001). Multivariate analysis demonstrated that α-SMA and lymph node metastasis were identified as independent predictive factors of metastasis.

CONCLUSION

Myofibroblasts represent an important prognostic factor for invasive growth that is translated into a poor clinical prognosis for patients with invasive breast cancer.