Colorectal cancer cells induce the formation of cancer-associated fibroblasts by activating the ERK signaling pathway in fibroblasts / 南方医科大学学报

OBJECTIVE@#To investigate the mechanism by which conditioned medium of colorectal cancer cells promotes the formation of cancer-associated fibroblasts (CAFs).@*METHODS@#Normal human colorectal fibroblasts (CCD-18Co cells) in logarithmic growth phase were treated with the conditioned media of colorectal cancer HCT116 cells (HCT116-CM) or Caco-2 cells (Caco-2-CM) alone or in combination with 300 nmol/L ERK inhibitor SCH772984. The expression levels of CAFs-related molecular markers were detected in the treated cells with real-time quantitative PCR (RT- qPCR) and immunofluorescence assay, and the changes in cell proliferation, colony formation and migration were assessed with RTCA, colony formation and wound healing assays; Western blotting was performed to detect the activated signaling pathways in the fibroblasts and the changes in CAFs formation after blocking of the signaling pathway.@*RESULTS@#HCT116-CM and Caco-2-CM significantly upregulated mRNA expression levels of CAFs markers (including α-SMA, FAP, FN and TGF-β) in CCD-18Co cells, and strongly promoted fibroblast transformation into CAFs (P < 0.05). The two conditioned media also promoted the proliferation, colony formation and migration of CCD-18Co cells (P < 0.05) and significantly increased the levels of α-SMA protein and ERK phosphorylation in the cells (P < 0.05). The ERK inhibitor SCH772984 obviously inhibited the expression of α-SMA and the transformation of CCD-18Co cells into CAFs induced by the conditioned medium of colorectal cancer cells (P < 0.05).@*CONCLUSION@#Colorectal cancer cells may induce the formation of colorectal CAFs by activating the ERK pathway in the fibroblasts.

Signal transducer and activator of transcription 3 and cancer associated fibroblasts jointly generate chemo-resistance and affect prognosis in epithelial ovarian cancer / 中华妇产科杂志

Objective: To investigate the mechanism of signal transducer and activator of transcription 3 (STAT3) and cancer associated fibroblasts (CAF) jointly generate chemo-resistance in epithelial-ovarian cancer and their effect on prognosis. Methods: A total of 119 patients with high-grade ovarian serous cancer who received surgery in Cancer Hospital of Chinese Academy of Medical Sciences from September 2009 to October 2017 were collected. The clinico-pathological data and follow-up data were complete. Multivariate Cox regression model was used to analyze the prognostic factors. Ovarian cancer tissue chips of patients in our hospital were prepared. EnVision two-step method immunohistochemistry was used to detect the protein expression levels of STAT3, the specific markers of CAF activation, fibroblast activating protein (FAP), and type Ⅰ collagen (COL1A1) secreted by CAF. The relationship between the expression of STAT3, FAP, COL1A1 protein and drug resistance and prognosis of ovarian cancer patients was analyzed, and the correlation between the expression of three proteins was analyzed. These results were verified through the gene expression and prognostic information of human ovarian cancer tissues collected in the GSE26712 dataset of gene expression omnibus (GEO) database. Results: (1) Multivariate Cox regression model analysis showed that chemotherapy resistance was an independent risk factor for overall survival (OS) of ovarian cancer (P<0.001). (2) The expression levels of STAT3, FAP, and COL1A1 proteins in chemotherapy resistant patients were significantly higher than those in chemotherapy sensitive patients (all P<0.05). Patients with high expression of STAT3, FAP, and COL1A1 had significantly shorter OS than those with low expression (all P<0.05). According to the human ovarian cancer GSE26712 dataset of GEO database, patients with high expression of STAT3, FAP, and COL1A1 also showed shorter OS than patients with low expression (all P<0.05), the verification results were consistent with the detection results of ovarian cancer patients in our hospital. (3) Correlation analysis showed that the protein level of STAT3 was positively correlated with FAP and COL1A1 in our hospital's ovarian cancer tissue chips (r=0.47, P<0.001; r=0.30, P=0.006), the analysis of GEO database GSE26712 dataset showed that the expression of STAT3 gene and FAP, COL1A1 gene were also significantly positively correlated (r=0.31, P<0.001; r=0.52, P<0.001). Conclusion: STAT3 and CAF could promote chemotherapy resistance of ovarian cancer and lead to poor prognosis.

Identification of SULF1 as a Shared Gene in Idiopathic Pulmonary Fibrosis and Lung Adenocarcinoma / 中国肺癌杂志

BACKGROUND@#Idiopathic pulmonary fibrosis (IPF) is an idiopathic chronic, progressive interstitial lung disease with a diagnosed median survival of 3-5 years. IPF is associated with an increased risk of lung cancer. Therefore, exploring the shared pathogenic genes and molecular pathways between IPF and lung adenocarcinoma (LUAD) holds significant importance for the development of novel therapeutic approaches and personalized precision treatment strategies for IPF combined with lung cancer.@*METHODS@#Bioinformatics analysis was conducted using publicly available gene expression datasets of IPF and LUAD from the Gene Expression Omnibus (GEO) database. Weighted gene co-expression network analysis was employed to identify common genes involved in the progression of both diseases, followed by functional enrichment analysis. Subsequently, additional datasets were used to pinpoint the core shared genes between the two diseases. The relationship between core shared genes and prognosis, as well as their expression patterns, clinical relevance, genetic characteristics, and immune-related functions in LUAD, were analyzed using The Cancer Genome Atlas (TCGA) database and single-cell RNA sequencing datasets. Finally, potential therapeutic drugs related to the identified genes were screened through drug databases.@*RESULTS@#A total of 529 shared genes between IPF and LUAD were identified. Among them, SULF1 emerged as a core shared gene associated with poor prognosis. It exhibited significantly elevated expression levels in LUAD tissues, concomitant with high mutation rates, genomic heterogeneity, and an immunosuppressive microenvironment. Subsequent single-cell RNA-seq analysis revealed that the high expression of SULF1 primarily originated from tumor-associated fibroblasts. This study further demonstrated an association between SULF1 expression and tumor drug sensitivity, and it identified potential small-molecule drugs targeting SULF1 highly expressed fibroblasts.@*CONCLUSIONS@#This study identified a set of shared molecular pathways and core genes between IPF and LUAD. Notably, SULF1 may serve as a potential immune-related biomarker and therapeutic target for both diseases.

Research Progress of Cancer-associated Fibroblasts in Hematolo- gic Malignancies --Review / 中国实验血液学杂志

Cancer-associated fibroblasts （CAF） are a key component of the tumor microenvironment, which can secrete a variety of cytokines, chemokines and growth factors, directly and indirectly support cancer cells, also alter the immune cellular environment by inhibiting the activity of immune effector cells and recruiting immunosuppressive cells, thereby allowing cancer cells to evade immune surveillance. CAF has been proven to be associated with the development, progression, and poor prognosis of solid tumors. However, the role of CAF in hematological malignancies is still unclear. This article reviews the research progress of CAF in hematological malignancies.

Research Status of Tumor-associated Fibroblasts Regulating Immune Cells / 中国肺癌杂志

Cancer-associated fibroblasts (CAFs) and tumor-infiltrating immune cells are the most essential components of the tumor microenvironment (TME). They communicate with each other in tumor microenvironment and play a critical role in tumorigenesis and development. CAFs are very heterogeneous and different subtypes of CAFs display different functions. At the same time, it can contribute to the regulation of the function of tumor-infiltrating immune cells and eventually result in the carcinogenesis, tumor progression, invasion, metastasis and other biological behaviors of tumors by producting various growth factors and cytokines etc. Based on the current research results at home and abroad, this paper reviews the recent research progress on the regulation of CAFs on infiltrating immune cells in tumor microenvironment.
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Glycolysis reprogramming in cancer-associated fibroblasts promotes the growth of oral cancer through the lncRNA H19/miR-675-5p/PFKFB3 signaling pathway / 国际口腔科学杂志·英文版

As an important component of the tumor microenvironment, cancer-associated fibroblasts (CAFs) secrete energy metabolites to supply energy for tumor progression. Abnormal regulation of long noncoding RNAs (lncRNAs) is thought to contribute to glucose metabolism, but the role of lncRNAs in glycolysis in oral CAFs has not been systematically examined. In the present study, by using RNA sequencing and bioinformatics analysis, we analyzed the lncRNA/mRNA profiles of normal fibroblasts (NFs) derived from normal tissues and CAFs derived from patients with oral squamous cell carcinoma (OSCC). LncRNA H19 was identified as a key lncRNA in oral CAFs and was synchronously upregulated in both oral cancer cell lines and CAFs. Using small interfering RNA (siRNA) strategies, we determined that lncRNA H19 knockdown affected proliferation, migration, and glycolysis in oral CAFs. We found that knockdown of lncRNA H19 by siRNA suppressed the MAPK signaling pathway, 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 3 (PFKFB3) and miR-675-5p. Furthermore, the lncRNA H19/miR-675-5p/PFKFB3 axis was involved in promoting the glycolysis pathway in oral CAFs, as demonstrated by a luciferase reporter system assay and treatment with a miRNA-specific inhibitor. Our study presents a new way to understand glucose metabolism in oral CAFs, theoretically providing a novel biomarker for OSCC molecular diagnosis and a new target for antitumor therapy.

In vitro Studies of Antitumor Activity of Vanadium Complexes with Orotic and Glutamic Acids / Estudos in vitro da Atividade Antitumoral de Complexos de Vanádio com Ácidos Órotico e Glutâmico / Estudios in vitro de la Actividad Antitumoral de Complejos de Vanadio con Ácidos Orótico y Glutámico

Introduction: Three vanadium complexes with orotic and glutamic acids, in their anion forms, were prepared and their in vitro cytotoxicity toward human lung fibroblasts (MRC-5), human hepatocellular carcinoma (HepG2) and human colorectal adenocarcinoma (Caco-2) are reported. Objective: Describe the synthesis and characterization of new vanadium complexes with orotic and glutamic acids, and test its antitumor activity against HepG2 and Caco-2. Method: The complexes were formulated as VO (oro), VO (α-glu) and VO (γ-glu) based on chemical, thermogravimetric analyses and infrared spectra. Results: Resazurin assay demonstrates its cytotoxicity against the HepG2 and Caco-2 cell lines with the IC50 ranging from 7.90 to 44.56 µmol.L-1. The cytotoxicity profiles indicate that the tumoral lines show more activity than the cells MRC-5, with selectivity indexes ranging from 1.58 to 8.96. Conclusion: The three complexes had better in vitro activity than cisplatin for both normal and cancer cell lines. The IC50 values are two to six times better for the cancer cell ines and five to seven times better for the normal cell lines. This study indicates that the complexes obtained are promising candidates for antitumor drugs.

Introdução: Foram preparados três complexos de vanádio com ácidos orótico e glutâmico, em suas formas aniônicas, e foi testada sua citotoxicidade in vitro para fibroblastos pulmonares humanos (MRC-5), carcinoma hepatocelular humano (HepG2) e adenocarcinoma colorretal humano (Caco-2). Objetivo: Descrever a síntese e caracterização de novos complexos de vanádio com ácidos orótico e glutâmico e testar sua atividade antitumoral contra HepG2 e Caco-2. Método: Os complexos foram formulados como VO (oro), VO (α-glu) e VO (γ-glu) com base em análises químicas, termogravimétricas e espectros no infravermelho. Resultados: O ensaio de resazurina demonstrou sua citotoxicidade contra as linhagens celulares HepG2 e Caco-2 com o IC50 variando de 7,90 a 44,56 µmol.L-1. Os perfis de citotoxicidade indicam que as linhas tumorais apresentam maior atividade que as células MRC-5, com índices de seletividade variando de 1,58 a 8,96. Conclusão: Os três complexos tiveram melhor atividade in vitro do que a cisplatina, tanto para linhagens celulares normais como cancerosas. Os valores de IC50 são de duas a seis vezes melhores para as linhagens celulares cancerosas e de cinco a sete vezes melhores para as linhagens celulares normais. Este estudo indica que os complexos obtidos são promissores candidatos a fármacos antitumorais.

Introducción: Tres complejos de vanadio con ácidos orótico y glutámico, en sus formas aniónicas, fueram preparados. Su citotoxicidad in vitro hacia los fibroblastos pulmonares humanos (MRC-5), el carcinoma hepatocelular humano (HepG2) y el adenocarcinoma colorrectal humano (Caco-2) son reportados. Objetivo: Los principales objetivos de este trabajo son describir la síntesis y caracterización de nuevos complejos de vanadio con ácidos orótico y glutámico y probar su actividad antitumoral contra el HepG2 y el Caco-2. Método: Los complejos fueron formulados como VO (oro), VO (α-glu) y VO (γ-glu) basados en análisis químicos, termogravimétricos y espectros infrarrojos. El ensayo de resazurina demuestra su citotoxicidad contra las líneas celulares HepG2 y Caco-2 con el IC50 que van de 7,90 a 44,56 µmol.L-1. Los perfiles de citotoxicidad indican que las líneas tumorales presentan mayor actividad que los MRC-5, con índices de selectividad que van de 1,58 a 8,96. Conclusión: Los tres complejos tuvieron mejor actividad in vitro que el cisplatino, tanto para líneas celulares normales como para líneas celulares cancerosas. Los valores del IC50 son de dos a seis veces mejores para las líneas celulares de cáncer y de cinco a siete veces mejores para las líneas celulares normales. Este estudio indica que los complejos obtenidos son candidatos prometedores para fármacos antitumorales.

Progress on cancer associated fibroblasts in tumor immunoregulation / 浙江大学学报·医学版

Cancer associated fibroblasts (CAFs) are important components of the tumor microenvironment. Through secreting of multiple growth factors, cytokines and proteases, CAFs play a significant role in regulating the recruitment and function of various innate immune cells and adaptive immune cells in tumor microenvironment. In addition, extracellular matrix secreted by CAFs can also promote the formation of immunosuppression and hypoxia of tumor microenvironment. Here, we review the progress on CAFs in regulation of immune cells and tumor immunity.

Potential Value of Cancer-Associated Fibroblasts in Hematological Malignancies--Review / 中国实验血液学杂志

Cancer-associated fibroblasts (CAF), as one of the most important components of tumor microenvironment, which plays important role in tumorigenesis, development, infiltration and metastasis of cancers. In a variety of solid tumors, CAF can even determine the fate of tumor cells. In view of its pivotal role in promoting tumor progression, CAF has recently become a therapeutic target for a variety of tumors. However, there are a few studies on CAF in hematological malignancies. Recent studies have found that the resistance, relapse of AML, MM, CLL and myelofibrosis of MPN closely relate with CAF, so targeting CAF can effectively enhance the killing effect of chemotherapy drugs on tumor cells, thus improve the efficacy, CAF is expected to become a new target for the treatment of hematological malignancies. This review summarizes recent advances in cancer-associated fibroblasts in hematological malignancies.

Fibromatosis intraabdominal mesentérica de identificación postmortem. Reporte de caso / Post mortem identification of Intra abdominal Mesenteric Fibromatosis. Case report

La Fibromatosis Intraabdominal es una entidad rara, de etiología desconocida, benigna, sin riesgo de metástasis, pero de comportamiento clínico muy agresivo. Se presenta el caso de femenina de 47 años de edad con paro de evacuaciones de un mes de evolución, marcada distensión abdominal e intolerancia a la vía oral, quien fue manejada en la emergencia de adultos de un hospital público, sin poder determinar su diagnóstico, quien falleció en su casa 30 días después de su última atención hospitalaria. El diagnostico post-mortem en la autopsia médico legal se estableció como Fibromatosis Intraabdominal. Se requiere un alto índice de sospecha ante esta enfermedad con el fin de proveer manejo adecuado a las complicaciones asociadas y disminuir la mortalidad atribuible a ellas...(AU)

Estaniocalcina 2 modula eventos importantes para a tumorigênese oral e é um marcador prognóstico para pacientes com carcinoma de células escamosas oral / Staniocalcin 2 modulates important events for oral tumorigenesis and is a prognostic marker for patients with oral squamous cell carcinoma

O hormônio glicoproteico estaniocalcina 2 (STC2) está envolvido na carcinogênese e progressão de muitos tipos de câncer. No entanto, seu significado clínico e mecanismos moleculares no carcinoma de células escamosas oral (CCEO) foram pouco estudados e permanecem incertos. O presente estudo investigou associações da expressão da STC2 com parâmetros clinicopatológicos e de sobrevida em pacientes com CCEO. Além disso, foram avaliados os efeitos biológicos causados pela redução dos níveis de STC2 em linhagens celulares de CCEO e fibroblastos associados ao câncer (do inglês CAF ­ carcinoma associated fibroblasts). A análise imunoistoquímica em 100 casos de CCEOs primários indicou que a superexpressão da STC2 foi associada com o parâmetro N do sistema TNM e foi um fator de risco independente para sobrevida específica da doença e sobrevida livre de doença em pacientes com CCEO. Usando ensaios in vitro, foi demonstrado que o silenciamento da STC2 em linhagens de CCEO promoveu a apoptose e reduziu a proliferação celular, migração, invasão e transição epitélio-mesenquimal. Análises adicionais revelaram que o CAF expressa maiores níveis de STC2 do que as células de CCEO. O silenciamento da STC2 no CAF reduziu a invasão celular do CCEO, sugerindo que a STC2 liberada por CAFs contribui para um fenótipo mais invasivo no CCEO. Esses resultados sugerem que a STC2 modula eventos importantes para a tumorigênese oral e pode ser um biomarcador prognóstico para pacientes com CCEO (AU).

The glycoprotein hormone stanniocalcin 2 (STC2) is involved in carcinogenesis and progression of several cancer types. However, its clinical significance and molecular mechanisms in oral squamous cell carcinoma (OSCC) have been partially studied and remain uncertain. In the present study, we investigated associations of STC2 expression with clinicopathological and survival parameters of OSCCs patients. We also determined the biological effects caused by STC2 downregulation in OSCC and cancer associated fibroblasts (CAF) cell lines. Immunohistochemical analysis in 100 cases of primary OSCC indicated that STC2 overexpression was associated with N stage (TNM staging) and was an independent risk factor for disease-specific survival and disease-free survival in patients with OSCC. Using in vitro assays, we demonstrated that STC2 knockdown in OSCC cell lines promoted apoptosis, and reduced cell proliferation, migration, invasion and epithelial-mesenchymal transition. Further analysis revealed that CAF expresses higher levels of STC2 than OSCC cells. Knockdown of STC2 in CAF reduced OSCC cell invasion, suggesting that STC2 released by CAF contributes to a more invasive phenotype in OSCC. These results suggest that STC2 modulates important events for oral tumorigenesis and can be a prognostic biomarker for OSCC (AU).

Analysis of gene expression changes associated with human carcinoma-associated fibroblasts in non-small cell lung carcinoma

BACKGROUND: This study aimed to investigate the gene expression changes associated with carcinoma-associated fibroblasts (CAFs) involving in non-small cell lung carcinoma (NSCLC). METHODS: We downloaded the GEO series GSE22862, which contained matched gene expression values for 15 CAF and normal fibroblasts samples, and series GSE27289 containing SNP genotyping for four matched NSCLC samples. The differentially expressed genes in CAF samples were identified using the limma package in R. Then we performed gene ontology (GO) and pathway enrichment analysis and protein-protein interaction (PPI) network construction using the identified DEGs. Moreover, aberrant cell fraction, ploidy, allele-specific copy number, and loss of heterozygosity (LOH) within CAF cells were analyzed using the allele-specific copy number analysis. RESULTS: We obtained 545 differentially expressed genes between CAF and normal fibroblasts samples. The up-regulated genes are mainly involved in GO terms such as positive regulation of cell migration and extracellular region, while the down-regulated genes participate in the lung development and extracellular region. Multiple genes including bone morphogenetic protein 4 (BMP4) and transforming growth factor, beta 3 (TGFB3) are involved in the TGF-ß signaling pathway. Genes including BMP4, TGFBI and matrix Gla protein (MGP) were hub genes. Moreover, no LOH event for BMP4 and MGP was found, that for sphingosine kinase 1 (SPHK1) was 70%, and for TGFBI was 40%. CONCLUSION: Our data suggested that BMP4, MGP, TGFBI, and SPHK1 may be important in CAFs-associated NSCLC, and the abnormal expression and high LOH frequency of them may be used as the diagnosis targets of CAFs in NSCLC.

Expression of CD10 in tumor-associated fibroblast of cancerized or recurrent colorectal adenomas / 浙江大学学报·医学版

To investigate the expression of CD10 in tumor-associated fibroblasts (TAF) in colorectal adenomas and its relation to cancerization and recurrence of adenoma.Tissue samples of low-grade adenoma (=50), high-grade adenoma (=50) and colorectal adenocarcinoma (=50) were collected, and tissue samples at the distal margin of corresponding colorectal lesions were taken as controls. The expression of CD10 in the stromal TAFs, and the expressions of β-catenin, Ki-67, p53 and CyclinD1 in tumor cells were detected by immunohistochemistry (Envision). The correlation of CD10 expression in stromal TAFs with the expressions of β-catenin, Ki-67, p53 and CyclinD1 in tumor cells was analyzed by Spearmen. One hundred samples of low-grade colorectal adenoma were collected, including 57 non-recurrent cases and 43 recurrent cases (16 cases of recurrent adenoma and 27 cases of recurrent adenocarcinoma); the expression of stromal TAF CD10 were determined and compared among groups.There was no TAF in normal colorectal mucosa. The expression rates of TAF CD10 in low-grade adenoma, high-grade adenoma and colorectal adenocarcinoma were 22%, 50% and 78%, respectively (all<0.05). The expression of Ki-67 and β-catenin in low-grade adenoma, high-grade adenoma, colorectal adenocarcinoma was on a rising trend (all<0.01). The expression of CyclinD1 in high-grade adenoma was higher than that in colorectal adenocarcinoma and low-grade adenoma (all>0.05). The expression of p53 in colorectal adenocarcinoma and high-grade adenoma was higher than that in low grade adenoma (all<0.01). The expression of TAF CD10 was correlated with the expression of p53, Ki-67 and β-catenin-nucleus(=0.264、0.307、0.320, all<0.01),but not correlated with CyclinD1 and β-catenin-membrane (=0.012、-0.073, all>0.05). The TAF CD10 level was significantly higher in low-grade adenoma with recurrence than that in those without recurrence (<0.05).The expression of CD10 in recurrent colorectal adenocarcinoma was higher than that in recurrent adenoma (<0.05).The expression of TAF CD10 is increased gradually in the process of adenoma-cancer, indicating that it may play an important role in the canceration of adenoma. Adenomas with high expression of CD10 TAF are likely to be recurrent and cancerized, and detection of TAF CD10 combined with p53, Ki-67 and β-catenin may be of value in predicting canceration or recurrence of colorectal adenoma.

Histological changes implicated in metastasis / Cambios histológicos implicados en metástasis

The process of malignancy emergence is associated with the acquisition of the capacity to invade other tissues. Several different biological processes have been described as involved in this process. Specifically, epithelial mesenchymal transition (EMT), a mechanism associated with embryogenesis and wound repair but also with mobility acquisition, is one of the concerned processes. In EMT an epithelial cell loses its epithelial characteristics, its junctions with neighbor cells and with the basal lamina and acquires mobility and mesenchymal characteristics. Also, factors of the tumor microenvironment have been described as involved. Tumor presence triggers a response in the surrounding tissue known as reactive stromal. It shows particular characteristics similar to those found in wound healing stroma: an increase of the fibroblast number and enhancing of the capillary density. The notable difference is the chronicity in the tumoral process. Of a high relevance seems to be the role of activated macrophages with a characteristic phenotype. Finally, cancer associated fibroblasts (CAF) are a type of cells found in tumors, developed from local tissue or possibly from bone marrow. CAF characteristically show a distinct morphology and secrete a high number of metalloproteases allowing tumoral cells advance through the tissue. Additionally, CAF have a direct effect on the survival of the epithelial cells. The three processes are interrelated and metastasis is probably caused by the effect of all of them and probably by other additional factors.

El desarrollo de malignidad está asociado con la adquisición de la capacidad de invadir otros tejidos. Varios procesos diferentes han sido asociados con la aparición de metástasis. Concretamente, la transición epitelio mesénquima (TEM), un mecanismo asociado con embriogénesis y reparación de heridas pero también con adquisición de movilidad, es uno de ellos. En la TEM, una célula epitelial pierde sus características epiteliales, sus uniones con las células vecinas y con la lámina basal y adquiere movilidad y características mesenquemáticas. También han sido asociados factores del microambiente del tumor. La presencia del tumor produce una respuesta en el tejido que lo rodea descrito como estroma reactivo. Sus características son similares a las del estroma de las heridas en proceso de curación: un incremento del número de fibroblastos y un aumento de la densidad de capilares. La gran diferencia es la cronicidad del proceso tumoral. De gran relevancia es el papel de los macrófagos activados que muestran un fenotipo característico. Finalmente, los fibroblastos asociados a cáncer (FAC) son un tipo de células encontradas en tumores, que se desarrollan a partir del tejido local o quizá de la médula ósea. Los FAC, de modo característico muestran una morfología diferente y secretan una gran cantidad de metaloproteasas permitiendo a la célula tumoral avanzar a través del tejido. Además, los FAC ejercen un efecto directo sobre la supervivencia de las células epiteliales. Los tres procesos están interrelacionados y la metástasis es causada probablemente por el efecto de todos ellos y probablemente por otros factores adicionales.