The prevalence and prognostic impact of tumor-infiltrating lymphocytes in uterine carcinosarcoma.

OBJECTIVE: To examine the prevalence and prognostic role of tumor microenvironment (TME) markers in uterine carcinosarcoma (UCS) through immunohistochemical characterization. METHODS: The internal database of our institution was queried out for women with UCS who underwent surgery and thereafter postoperative chemotherapy with carboplatin and paclitaxel between January 2012 and December 2017. Tissue microarrays containing surgical samples of UCS from 57 women were assessed by immunohistochemistry for CD3, CD4, CD8, FOXP3, PD-1, PD-L1, and PD-L2. RESULTS: The mean age was 65.3 years (range, 49 to 79 years). For the epithelial component (E), CD3_E and CD4_E were highly expressed in 38 (66.7%) and in 40 (70.1%) patients, respectively, and were significantly associated with more advanced stages (p = 0.038 and p = 0.025, respectively). CD8_E was highly expressed in 42 (73.7%) patients, FOXP3_E 16 (28.1%), PD-1_E 35 (61.4%), PD-L1_E 27 (47.4%) and PD-L2_E 39 (68.4%). For the sarcomatous component (S), the prevalence of high expression was: CD3_S 6 (10.5%), CD4_S 20 (35.1%), CD8_S 44 (77.2%), FOXP3_S 8 (14%), PD-1_S 14 (24.6%), PD-L1_S 14 (24.6%) and PD-L2_S 8 (14%). By multivariate analysis, the CD8/FOXP3_S ratio (p = 0.026), CD4_E (p = 0.010), PD-L1_E (p = 0.013) and PD-L1_S (p = 0.008) markers significantly influenced progression-free survival. CD4/FOXP3_S ratio (p = 0.043), PD-1_E (p = 0.011), PD-L1_E (p = 0.036) and PD-L1_S (p = 0.028) had a significant association with overall survival. CONCLUSION: Some differences in UCS clinical outcomes may be due to the subtype of TILs and PD-1/PD-L1 axis immune checkpoint signaling.

Co-expression Analysis of Genes and Tumor-Infiltrating Immune Cells in Metastatic Uterine Carcinosarcoma.

Uterine carcinosarcoma (UCS) is a malignant tumor with a high tendency to invasion and metastasis. However, the underlying invasion and metastasis mechanisms of UCS remain poorly understood. Genetic alteration and tumor-infiltrating immune cells play important roles in tumorigenesis, progression, and metastasis. To better understand the underlying mechanisms of UCS, we screened tumor-infiltrating immune cells by applying CIBERSORT algorithm and constructed nomograms to predict the prognosis of UCS patients based on metastasis-specific tumor-infiltrating immune cells and genes, and demonstrated their utility by the high AUC values. Combining gene co-expression and experimental validation results, we propose a potential mechanism of AK8, MPZ, and mast cells activated might play important parts in UCS metastasis.

Immunogenomic landscape of gynecologic carcinosarcoma.

OBJECTIVE: Carcinosarcoma (CS) of the uterus or ovary is a rare, biphasic tumor comprising epithelial and mesenchymal elements, and exhibits more aggressive clinical features than its carcinoma counterpart. Four molecular subtypes of CS were recently established based on genomic aberration profiles (POLE, MSI, CNH, and CNL) and shown to be associated with multiple clinicopathological parameters, including patient outcomes. However, the role of the immune microenvironment in CS remains unclear. Here, we investigated the influence of the immune cells that infiltrate CS to better understand the immunological status of gynecological CS. METHODS: Tumor immune microenvironmental analyses on CS samples were performed using immune cell profiling with RNA-seq, transcriptomic subtyping with microenvironmental genes, and T-cell receptor repertoire assay. Carcinoma and sarcoma elements from CS samples were also assessed separately. RESULTS: Relying on estimations of tumor-infiltrating cell types from RNA-seq data, POLE and MSI (hypermutator) tumors showed an enrichment of M1 macrophages, plasma cells and CD8+ T cells, whereas CNH and CNL (non-hypermutator) tumors had high levels of M2 macrophages. Further subclassification by immune-related, non-cancer genes identified a fraction of tumors with distinct patient outcomes, particularly those with the CNH genomic aberration subtype. T-cell heterogeneity was independently correlated with prolonged progression-free survival. Differential analysis of carcinoma and sarcoma elements identified many shared mutations but there was little overlap in the T-cell receptor repertoire between the two elements. CONCLUSIONS: Tumor immune microenvironmental analyses could offer potential clinical utility in the stratification of gynecological CS above classification by genomic aberration subtype alone.

An immunohistochemical analysis of CD3, PD-L1, and CTLA-4 expression in carcinosarcomas of the gynecological tract and their metastases.

BACKGROUND: Carcinosarcoma of the gynecological tract is a rare tumor with a dismal prognosis. Its immune micro-environment has not been sufficiently studied. AIM OF THE STUDY: To study the immune micro-environment of gynecological carcinosarcomas. MATERIAL AND METHODS: Sixty-nine surgical specimens from 37 different patients, including 34 primary tumors and 35 metastases, were immunohistochemically studied for the expression of CD3, PD-L1, and CTLA-4. Clinical and histological features were recorded and correlated with immunohistochemical factors. RESULTS: Twenty-two cases involved the uterine corpus, 1 the uterine cervix, and 14 the adnexa. The overall survival ranged from 2 to 156 months, with a median survival of 16 months. CD3 expression was more frequent at the sarcomatous than the carcinomatous component. CTLA-4 expression was higher at the carcinomatous than the sarcomatous component. PD-L1 was negative in all cases studied. Tumor relapse, metastasis presence, metastasis localization, and overall survival did not correlate with CD3 or CTLA-4 expression. CONCLUSION: PD-L1 expression is not a feature of gynecological carcinosarcomas, despite a relatively frequent lymphocytic reaction. CTLA-4 expression is sometimes found in these tumors.

The characteristic of tumor immune microenvironment in pulmonary carcinosarcoma.

Pulmonary carcinosarcoma (PCS) is a rare but aggressive neoplasm, due to late diagnosis and early metastasis. Surgery combined with radiotherapy is a standard treatment. However, PCS features an easy relapse after surgery resection and resistance to chemotherapy and radiotherapy. Tumor immune microenvironment reflects tumor immunophenotyping and affects immunotherapy efficiency. This review summarized current studies on the characteristic of tumor immune microenvironment in PCS and discussed the potential of immunotherapy combined with other regimes strategy as a candidate for treatments in PCS.

Sarcomatoid carcinoma presenting as cancers of unknown primary: a clinicopathological portrait.

BACKGROUND: Sarcomatoid carcinoma of unknown primary (SCUP) is a rare entity of either poorly differentiated carcinoma with sarcoma-like differentiation or a true mixed lineage neoplasm. Limited data regarding clinicopathological profile and management exists. METHODS: We retrospectively reviewed the MD Anderson Cancer of Unknown Primary database and tumor registry to identify 48 SCUP patients between 2001 and 2017. Patient characteristics, pathology, molecular diagnostics, treatments, and outcomes were obtained. Kaplan-Meier method was used to estimate overall survival (OS) and compared using log rank test. RESULTS: Median age at diagnosis was 59 years (range 27-86). Majority of patients were female (58%) and presented with ≥3 metastatic sites (52%), commonly lymph node (50%), bone (42%), lung (27%), and liver (21%). First line treatment included chemotherapy (35%), surgery (27%), and radiation (24%). Gemcitabine and docetaxel (18%) was the most common chemotherapy regimen. Median OS for entire cohort was 11 months (95% CI: 5.6 to 16.4). Poor performance status (PS), > 1 metastatic site, elevated lactate dehydrogenase (LDH), and high neutrophil-to-lymphocyte ratio (NLR) were significantly associated with worse OS on univariate analyses. On multivariate analyses, poor PS (HR 8.7; 95%CI: 3.0-25.0; p <  0.001) and high NLR (HR 3.4; 95%CI: 1.3-8.8; p = 0.011) emerged as independent prognostic factors for OS. CONCLUSIONS: SCUP is a rare presentation with an aggressive clinical course and limited survival. Diagnosis is difficult to make and requires careful review and synthesis of histology, immunohistochemistry, and molecular diagnostics. Chemotherapy resistance remains a challenge. Early mutational profiling is warranted, and clinical trial participation should be encouraged for this subset.

The Adrenal Gland as a Sanctuary Site of Metastases After Pembrolizumab Treatment: A Case Series.

Therapeutic agents targeting the PD-1/PD-L1 axis have shown durable clinical responses in patients with various cancer types. Although objective responses are common, intrapatient heterogeneous responses have been described, and the mechanism for the different organ responses remains unknown. We present a series of patients in whom a lack of response was noted solely in the adrenal glands. This is the first case series describing 3 patients with heterogeneous patterns of response to pembrolizumab with progression of adrenal metastatic disease despite objective response (complete or partial response) in all other sites of metastatic disease. Two patients, one with melanoma and one with uterine carcinosarcoma, underwent robotic adrenalectomy for enlarging adrenal metastases. An additional patient with melanoma underwent laparotomy with attempted resection, but infiltration of the adrenal tumor into the inferior vena cava prohibited safe excision. This report provides additional insight into the heterogeneous patterns of disease response to anti-PD-1 therapy, highlighting the adrenal gland as a potential sanctuary site for this immunotherapy. These cases display the potential benefit of early surgical resection in this scenario and the pitfalls of delaying referral to a surgeon for assessment of operative intervention.

Ex vivo expanded tumour-infiltrating lymphocytes from ovarian cancer patients release anti-tumour cytokines in response to autologous primary ovarian cancer cells.

Epithelial ovarian cancer (EOC) is the leading cause of gynaecological cancer-related death in Europe. Although most patients achieve an initial complete response with first-line treatment, recurrence occurs in more than 80% of cases. Thus, there is a clear unmet need for novel second-line treatments. EOC is frequently infiltrated with T lymphocytes, the presence of which has been shown to be associated with improved clinical outcomes. Adoptive T-cell therapy (ACT) using ex vivo-expanded tumour-infiltrating lymphocytes (TILs) has shown remarkable efficacy in other immunogenic tumours, and may represent a promising therapeutic strategy for EOC. In this preclinical study, we investigated the efficacy of using anti-CD3/anti-CD28 magnetic beads and IL-2 to expand TILs from freshly resected ovarian tumours. TILs were expanded for up to 3 weeks, and then subjected to a rapid-expansion protocol (REP) using irradiated feeder cells. Tumours were collected from 45 patients with EOC and TILs were successfully expanded from 89.7% of biopsies. Expanded CD4+ and CD8+ subsets demonstrated features associated with memory phenotypes, and had significantly higher expression of key activation and functional markers than unexpanded TILs. Expanded TILs produced anti-tumour cytokines when co-cultured with autologous tumour cells, inferring tumour cytotoxicity. Our findings demonstrate that it is possible to re-activate and expand tumour-reactive T cells from ovarian tumours. This presents a promising immunotherapy that could be used sequentially or in combination with current therapeutic strategies.

SYD985, a Novel Duocarmycin-Based HER2-Targeting Antibody-Drug Conjugate, Shows Antitumor Activity in Uterine and Ovarian Carcinosarcoma with HER2/Neu Expression.

Purpose: Carcinosarcomas (CS) are highly aggressive gynecologic malignancies containing both carcinomatous and sarcomatous elements with heterogeneous HER2/neu expression. We compared the efficacy of SYD985 (Synthon Biopharmaceuticals BV), a novel HER2-targeting antibody-drug conjugate (ADC), to trastuzumab emtansine (T-DM1, Genentech-Roche) against primary uterine and ovarian CS.Experimental Design: Eight primary CS cell lines were evaluated for HER2/neu surface expression by IHC and gene amplification by FISH assays. The in vitro experiments included cytotoxicity, antibody-dependent cellular cytotoxicity (ADCC), proliferation, viability, and bystander killing. In vivo activity was studied in mouse xenograft and patient-derived xenograft (PDX) models.Results: SYD985 and T-DM1 induced similar levels of ADCC against CS cell lines with low and high HER2/neu expression when challanged in the presence of effector cells. In contrast, SYD985 was 7- to 54-fold more potent than T-DM1 in the absence of effector cells. SYD985, unlike T-DM1, was active against CS demonstrating low or heterogeneous HER2/neu expression. Specifically, the mean IC50 values were 0.060 µg/mL and 3.221 µg/mL (P < 0.0001) against HER2/neu 0/1+ cell lines and 0.013 µg/mL and 0.096 µg/mL (P < 0.0001) against HER2/neu 3+ cell lines for SYD985 versus T-DM1, respectively. Importantly, unlike T-DM1, SYD985 induced efficient bystander killing of HER2/neu 0/1+ tumor cells admixed with HER2/neu 3+ cells. In vivo studies confirmed that SYD985 is more active than T-DM1 in CS and highly effective against HER2/neu expressing xenografts and PDX.Conclusions: SYD985 may represent a novel and highly effective ADC against HER2-expressing CS. Clinical studies with SYD985 in patients harboring chemotherapy-resistant CS with low/moderate and high HER2 expression are warranted. Clin Cancer Res; 23(19); 5836-45. ©2017 AACR.

[Sinonasal teratocarcinosarcoma: clinicopathologic study and analysis].

OBJECTIVE: To study the clinicopathologic features, immunophenotype, diagnosis and differential diagnosis of Sinonasal teratocarcinosarcoma (SNTCS). METHOD: The clinical findings, morphologic features and immunohistochemical markers in one case of SNTCS were studied, and the relevant literatures were reviewed. RESULT: The Tumor tissue is composed of three layers, with mature and immature squamous epithelium nests, neural epithelial cells and olfactory neuroblastoma-like cells derived of ectoderm; Sarcomatoid components and bone tissue derived of mesoderm; The glandular and tubular structures part of which is adenocarcinoma and respiratory epithelium derived of endoderm; The fetal clear cell squamous epithelium is typical. In addition, diffuse large cytoplasm-with high light and cytoplasm with dark light has no obviously boundery. Immunohistochemical staining showed immune markers of different germ layers corresponding, squamous epithelium, glandular epithelium and respiratory epithelium were positive for CK and EMA, neural epithelial cells and olfactory neuroblastoma-like cells were positive for S-100, NSE and Syn, sarcomatoid area was positive for Vim, light dye area was positive for Vim, CD99 and CK, dark area was positive for NSE and GFAP. CONCLUSION: SNTCS is a rare malignant tumor with the features of teratoma and carcinosarcoma, its histopathological and immunohistochemical features were typical, should be more drawn and sliced to avoid misdiagnosis and missed diagnosis.

Immunological response after WT1 mRNA-loaded dendritic cell immunotherapy in ovarian carcinoma and carcinosarcoma.

BACKGROUND: Dendritic cell (DC)-based immunotherapy is an emerging new treatment option in ovarian cancer, an important cause of cancer-related mortality. PATIENTS AND METHODS: One patient with ovarian carcinosarcoma (OCS) and one with serous ovarian cancer (SOC) received four weekly vaccinations of autologous DCs electroporated with mRNA coding for the Wilms' tumor gene 1 (WT1). Safety, feasibility and immunogenicity were assessed. RESULTS: Vaccination was feasible without toxicity. In an ex vivo antigen re-stimulation assay of peripheral blood mononuclear cells, both patients showed increasing cluster of differentiation 137 (CD137+) antigen-specific T-cells and interleukin 10 (IL-10) production post-vaccination. Moreover, interleukin-2 (IL-2) production increased (OCS) as well as interferon-gamma (IFN-γ) and tumor necrosis factor-alpha (TNF-α) (SOC). Disease in patients progressed after four vaccines and patients continued with conventional therapies. After cessation of immunotherapy, they had an extended survival of 19 (OCS) and 12 (SOC) months. CONCLUSION: To our knowledge, we report for the first time the feasibility and T-cell immunogenicity of WT1 mRNA-loaded DC immunotherapy in ovarian cancer.

Sarcomatoid carcinoma of the bladder after simultaneous kidney-pancreas transplant: a case report and review of the literature.

Carcinosarcoma and sarcomatoid carcinoma of the bladder after organ transplantation is higher in comparison to the general population but overall occurrence is still very uncommon. Due to the decreased immunitary response effects of antirejection drugs, these cancers have aggressive course and respond poorly to treatment. Bladder drained pancreatic transplants are associated with a number of urologic challenges that can delay the diagnosis and the treatment of malignancies of the genito-urinary system. The authors present a case of a rare sarcomatoid carcinoma of the bladder following bladder drained simultaneous kidney and pancreas transplant and discuss its pathogenesis and clinical management.

Two cases of breast carcinoma with osteoclastic giant cells: are the osteoclastic giant cells pro-tumoural differentiation of macrophages?

Breast carcinoma with osteoclastic giant cells (OGCs) is characterized by multinucleated OGCs, and usually displays inflammatory hypervascular stroma. OGCs may derive from tumor-associated macrophages, but their nature remains controversial. We report two cases, in which OGCs appear in common microenvironment despite different tumoural histology. A 44-year-old woman (Case 1) had OGCs accompanying invasive ductal carcinoma, and an 83-year-old woman (Case 2) with carcinosarcoma. Immunohistochemically, in both cases, tumoural and non-tumoural cells strongly expressed VEGF and MMP12, which promote macrophage migration and angiogenesis. The Chalkley count on CD-31-stained sections revealed elevated angiogenesis in both cases. The OGCs expressed bone-osteoclast markers (MMP9, TRAP, cathepsin K) and a histiocyte marker (CD68), but not an MHC class II antigen, HLA-DR. The results indicate a pathogenesis: regardless of tumoural histology, OGCs derive from macrophages, likely in response to hypervascular microenvironments with secretion of common cytokines. The OGCs have acquired bone-osteoclast-like characteristics, but lost antigen presentation abilities as an anti-cancer defense. Appearance of OGCs may not be anti-tumoural immunological reactions, but rather pro-tumoural differentiation of macrophage responding to hypervascular microenvironments induced by breast cancer.

Carcinosarcoma of the esophagus.

Carcinosarcoma of the esophagus is a rare neoplasm characterized histologically by presence of carcinomatous and sarcomatous elements. Case report of carcinosarcoma of the esophagogastric junction whose morphological and immunohistochemical features makes it quite distinctive from other tumours is presented. It was an ulcerated lesion diagnosed in an elderly Afghan lady located 34 cms from the incisor teeth. The patient was a smoker.

Gastric carcinosarcoma presenting as a huge epigastric mass.

Gastric carcinosarcoma often presents with an elevated lesion or increased thickness of the stomach wall. Histological diagnosis is achieved using conventional hematoxylin and eosin staining to confirm the coexistence of both epithelial and mesenchymal elements. We report a case of gastric carcinosarcoma presenting as a large mass in the epigastric region. Specimens obtained by endoscopic biopsy and surgical excision showed diffuse proliferation of atypical cells in sheet formation. No mucus production or glandular structures were apparent, but immunoreactivity for both epithelial and mesenchymal markers was noted. These findings led to a definitive diagnosis of gastric carcinosarcoma. Immunohistochemical analysis is useful for the early diagnosis and treatment of gastric carcinosarcoma.

Carcinosarcoma of the parotid gland: an unusual case with large-cell neuroendocrine carcinoma and rhabdomyosarcoma.

We report a case of carcinosarcoma of the parotid gland in a 72-year-old Japanese man. The patient noticed a rapidly enlarging hard mass in the right parotid gland. He underwent radical parotidectomy with cervical lymph node dissection. The resected tumor measured 3.5 x 4.5 cm and histopathologically showed carcinomatous and sarcomatous components. The carcinomatous component consisted of large-cell neuroendocrine carcinoma (LCNEC), squamous cell carcinoma and adenocarcinoma not otherwise specified, while the sarcomatous component included spindle cell sarcoma not otherwise specified, so-called myxosarcoma and rhabdomyosarcoma. The LCNEC component was predominant within the whole tumor. The diagnoses of LCNEC and rhabdomyosarcoma were also confirmed immunohistochemically. With regard to histopathogenesis, based on the lack of histopathological evidence and antecedent history of pleomorphic adenoma, we considered the present case to be de novo, not expleomorphic adenoma.

Effusion cytodiagnosis of carcinosarcoma derived from the female genital tract: immunohistochemical features of MMP-7 and Ki-67 and immunofluorescence double staining analyses of eight cases.

OBJECTIVE: Expression of Matrix metalloproteinase 7 (MMP-7) and Ki-67 by carcinoma components (CCs) and sarcoma components (SCs) in carcinosarcoma of the female reproductive organs has been investigated by conventional methods, but analysis with immunohistochemical staining of multiple antigens has not been reported. We report the profiles of expression of MMP-7 and Ki-67 in carcinosarcoma determined with immunohistochemical staining techniques. METHODS: We used antibodies against epithelial antigen (EA), epithelial membrane antigen (EMA), and vimentin for immunofluorescence double staining of ascitic fluid in eight cases of carcinosarcoma of female reproductive organs. We also used immunohistochemical triple staining to compare MMP-7 and Ki-67 expression between CCs and SCs in the primary site of carcinosarcoma. RESULTS: Immunofluorescence analysis revealed that all neoplastic cells in the ascitic fluid were positive for EA or EMA, indicating that these cells were CCs. Immunohistochemical analyses of the primary organ of carcinosarcoma revealed that MMP-7 was expressed on CCs in four of eight cases of carcinosarcoma, whereas MMP-7 was not expressed on SCs. The average Ki-67 labeling index (LI) in CCs and SCs was 51.8% and 28.6%, respectively. The difference in Ki-67 LI between CCs and SCs was statistically significant (t test for paired samples, P = 0.0173). CONCLUSIONS: This is the first study to examine carcinosarcoma of the female reproductive organ by immunohistochemical staining for multiple antigens, which allows analysis of mixed tumor elements. In addition, we found that expression of MMP-7 and the average Ki-67 LI differ between CCs and SCs in carcinosarcoma. The predominance of CCs as the malignant cells in the ascitic fluid may be due to cytological differences between CCs and SCs of carcinosarcoma.

Metaplastic carcinoma of the breast in an HIV-positive patient: a case report.

BACKGROUND: Metaplastic carcinoma of the breast is a rare neoplasm that causes diagnostic difficulty on fine needle aspiration smears. Breast carcinoma in HIV-infected patients occurs at a relatively early age, with increased bilateral disease, unusual histology, and early metastatic spread with a poor outcome. CASE: A case of metaplastic carcinoma of the breast arose in a 36-year-old woman who was seropositive for HIV. In the absence of a sarcomatous component and presence of obvious ductal differentiation on aspirates, a diagnosis of high grade infiltrating duct carcinoma, not otherwise specified, was made on fine needle aspiration cytology (FNAC). CONCLUSION: This case underlines the limitations of FNAC in the diagnosis of metaplastic carcinoma of the breast. It also shows that it is imperative to maintain a high index of suspicion for rare pathologies in immunocompromised patients.

Lymphocyte-facilitated tumour cell adhesion to endothelial cells: the role of high affinity leucocyte integrins.

AIM: Lymphocytes transiently express an active form of the beta_2 integrin LFA-1 (LFA-1Af) which has conformational changes in extracellular domains enabling higher affinity binding to the ligand ICAM-1. In this study, we investigated the role of lymphocytes bearing LFA-1Af as potential mediators of binding of ICAM-1-positive tumour cells to endothelium. METHODS: LFA-1 expression on 51Cr-PBLs was modulated in order to express high affinity LFA-1Af and conjugates were formed with 35S-labelled COLO526. The binding of the conjugates to resting or IL-1beta-stimulated human umbilical vein endothelial cells (HUVECs) was then assessed via a modified radioactive HUVEC binding assay. In addition, the binding of PBL-COLO526 conjugates to HUVECs was demonstrated by confocal microscopy. RESULTS: The binding of COLO526 to endothelial cells did not change significantly between unstimulated and stimulated HUVECs. In addition, pre-incubating the COLO526 with fresh PBLs did not significantly alter the binding of COLO526 to resting or activated HUVECs; whereas, in the presence of PBLs with LFA-1Af, the COLO526 conjugate binding dramatically increased from basal levels to 41% on resting HUVECs and 81% on stimulated HUVECs. COLO526-PBL(LFA-1Af) conjugate adhesion to stimulated HUVECs was inhibited by blocking antibody to LFA-1 (50%), VLA-4 (32%) or L-selectin (40%). Antibodies to the HUVEC adhesion molecules ICAM-1, VCAM-1 and E-selectin also inhibited COLO526-PBL(LFA-1Af) conjugate binding to activated HUVECs by 79, 60 and 73%, respectively. CONCLUSIONS: PBLs bearing LFA-1Af can enhance COLO526 adhesion to both resting and activated HUVECs. Furthermore, blocking studies demonstrate that a range of pathways are involved in this phenomenon (LFA-1/ICAM-1, VLA4/VCAM-1, L-selectin/E-selectin). These studies have identified a novel alternative pathway for lymphocyte-facilitated tumour cell adhesion to endothelial cells.