Immunotherapy Applications for Thymine Dimers and WT1 Antigen in Renal Cancers: A Comparative Statistical Analysis.

Renal cell carcinoma (RCC) remains incurable in advanced stages. Biomarkers have proven to be quite useful in cancer therapeutics. Herein, we provide a comparative/integrative statistical analysis of seminal immunohistochemistry (IHC) findings for Wilms' Tumor 1 antigen (WT1) and thymine dimers (TDs), emerging as atypical, yet promising, potential biomarkers for RCCs. We assessed WT1/TD reactivity in adult RCC tumor cells, tumor microenvironment (TME), and tumor-adjacent healthy renal tissue (HRT). WT1 positivity was scarce and strictly nuclear in tumor cells, whereas TD-reactive tumor tissues were prevalent. We report statistically significant positive correlations between the density of reactive RCC cellularity and the intensity of nuclear staining for both biomarkers (WT1 - rho = 0.341, p-value = 0.036; TDs - rho = 0.379, p-value = 0.002). RCC stromal TME TD-positivity was much more frequent than WT1 reactivity, apparently proportional to that of the proper RCC cellularity and facilitated by extensive RCC inflammatory infiltration. TDs exhibited nuclear reactivity for most TME cell lines, while RCC TME WT1 expression was rare and inconsistent. In HRTs, TDs were entirely restricted to renal tubular cells, the likely cellular progenitor of most conventional RCC subtypes. In lieu of proper validation, these early findings have significant implications regarding the origins/biology of RCCs and may inform RCC therapeutics, both accounting for the high frequency of immunotherapy-permissive frameshift indels in RCCs, but also hinting at novel predictive clinical tools for WT1-targeted immunotherapy. Overall, the current study represents a meek yet hopefully significant step towards understanding the molecular biology and potential therapeutic targets of RCCs.

Mast Cell: A Mysterious Character in Skin Cancer.

Cutaneous malignancies represent a real concern and burden for the healthcare system, not only due to their increased frequency, but also due to the significant number of deaths attributed to these types of cancer. The genesis of tumors, their progression and metastasis are highly complex and researched subjects; apparently, mast cells (MCs) constitute an important piece in the complicated jigsaw puzzle of cancer. This article reviews the current knowledge of the roles MCs might play in the development of cutaneous malignancies. Besides their well-known and studied role in allergic reactions, MCs are linked to multiple and various disorders, including cancer. MCs exhibit incredible heterogeneity, being able to secrete numerous mediators that influence the tumor microenvironment and tumor cells. They are involved in many physiological and pathological processes, such as inflammation and angiogenesis. In this context, it is paramount to explore the advancements made so far in elucidating the roles that MCs have in skin cancer because they might provide valuable therapeutic targets in the future. Controversial and conflicting results were obtained across the studies examined.

The Follicular Dendritic Cells and HPV 18 Interrelation in Head and Neck Squamous Cell Carcinomas of the Larynx.

Background and Objectives: Even if they are cells of controversial origin (mesenchymal, perivascular, or fibroblastic), follicular dendritic cells (FDC) are present in all organs. The aim of this study was to establish the FDC expression pattern and its interrelation with HPV 18 expression in laryngeal squamous cell carcinoma (LSCC). Materials and Methods: Fifty-six cases of LSCC were evaluated by simple and double immunostaining. The following score was used: 0 (negative or few positive cells), 1 (10-30% of positive cells), 2 (30-50% of cells), and 3 (over 50% of cells). Results: The expression of CD 21-positive cells with dendritic morphology (CDM) was noticed in the intratumoral area of conventional (well and poorly differentiated types and HPV 18 positive cases with a value of 2 for the score) and papillary types (HPV-18 negative cases with a score of 1). The highest value of 2 for the score of CDM in HPV-18 positive cases was found in the peritumoral area of well- and poorly-differentiated conventional LSCCs. A significant correlation was found between scores of CDM from the intratumoral area and those of the peritumoral area (p = 0.001), between CDM and non-dendritic morphology cells (NDM) of the intratumoral area (p = 0.001), and between HPV-18 status and peritumoral NDM cells (p = 0.044). Conclusions: The FDC and NDM cell score values of intratumoral and peritumoral areas may represent important parameters of LSCCs. This may contribute to a better stratification of laryngeal carcinoma cases and the individualized selection of clinical treatment protocols.

Chloride Intracellular Channel Protein 1 Expression and Angiogenic Profile of Liver Metastasis of Digestive Origin.

Chloride intracellular channel 1 (CLIC1) is involved in cell migration and metastasis. The histological growth patterns of liver metastasis are as follows: desmoplastic (d-HGP), replacement (r-HGP), pushing (p-HGP), and mixed. The aim of this study was to evaluate the relation between HGP, angiogenesis, and CLIC1 expression. Materials and Methods: A total of 40 cases of primary tumors and their LM: d-HGP (12 cases), r-HGP (13 cases), and p-HGP (15 cases), were evaluated through simple and double immunostaining. CLIC1 assessment was conducted as follows: scores of 0 (less than 10% of positive cells), 1 (10-30%), 2 (30-50%), or 3 (more than 50%) were assigned. Heterogeneous CLIC1 expression was found. CLIC1 in primary tumors correlated with grade G for all cases of LM with a p-HGP (p = 0.004). The CLIC1 score for LMs with an r-HGP correlated with grade G of the corresponding primary tumor (p = 0.027). CLIC1 and CD34+/Ki67+ vessels (p = 0.006) correlated in primary tumors. CLIC1 in primary tumors correlated with CD34+/Ki67+ vessels of LMs with a d HGP (p = 0.024). Conclusions: The CLIC1 score may have prognostic value, mainly for LMs with a p-HGP and r-HGP, and therapeutic value for LMs with a d-HGP.

Mast Cells as an Indicator and Prognostic Marker in Molecular Subtypes of Breast Cancer.

BACKGROUND/AIM: Mast cells (MCs) represent the most controversial non-malignant element of the tumor microenvironment. Our aim was to study how MCs density and distribution (intratumoral-MCit versus peritumoral-MCpt) relate to tumor grade and molecular subtypes. MATERIALS AND METHODS: MCs tryptase immunohistochemistry was performed on 80 cases of breast carcinomas. RESULTS: For Luminal A tumors, a partial correlation was detected between MCit and progesterone receptor (PR) (p=0.005). Luminal B tumors showed a significant correlation between MCpt and age (p=0.009), estrogen receptor (ER) (p=0.017) and PR (p=0.035). MCit and MCpt were strongly interrelated in this subtype (p=0.002) and in triple-negative breast cancers (p=0.002). In HER2 subtype, MCpt tumors were significantly correlated with HER2 (p=0.044). In G2 tumors, MCpt correlated with ER (p=0.015) and PR (p=0.038) while in G3 tumors ER correlated with both MCit (p=0.009) and MCpt (p=0.000487) tumors. CONCLUSION: MCs dynamics are strongly influenced by hormone receptors and HER2 status. MCit increased in aggressive tumor types and is a worse prognostic factor.

Mast Cells: Key Players in the Shadow in Oral Inflammation and in Squamous Cell Carcinoma of the Oral Cavity.

Although mast cells (MCs) have been discovered over 130 years ago, their function was almost exclusively linked to allergic affections. At the time being, it is well known that MCs possess a great variety of roles, in both physiologic and pathologic conditions. In the oral tissues, MCs release different proinflammatory cytokines, tumor necrosis factor alpha (TNF-α), that promote leukocyte infiltration in various inflammatory states of the oral cavity. These cells play a key role in the inflammatory process and, as a consequence, their number changes in different pathologic conditions of the oral cavity, like gingivitis, periodontitis, and so on. MCs also represent a rich source of proteases, especially of mast cell tryptase and chymase, which directly degrade the extracellular matrix through their proteolytic activity and thus indirectly stimulate angiogenesis and facilitate invasion and metastasis. It may be stated that mast cells could have an impact on primary tumor development, progression, and metastases in oral squamous cell carcinoma. By understanding the role of mast cells in the pathogenesis of different inflammatory and tumor diseases of the oral cavity, these cells may become therapeutic targets that could possibly improve the prognosis and survival of these patients.

Epidermal Growth Factor Receptor (EGFR) and Keratin 5 (K5): Versatile Keyplayers Defining Prognostic and Therapeutic Sub-classes of Head and Neck Squamous Cell Carcinomas.

Molecular classifications of several malignancies are already accepted and applied in clinical practice. For head and neck squamous cell carcinomas (HNSCCs) there exist few and controversial data regarding their stratification on distinct groups or sub-groups and thus, none of them are validated as useful tools for diagnosis and therapy. Starting from the highly expressed markers in HNSCC (epidermal growth factor receptor, keratin 5 and E cadherin) we proposed to identify distinct HNSCC sub-groups with a potential impact on prognosis and therapy. Complex analysis of immunohistochemical expression for six surrogate markers (EGFR, p53, Bcl2, CD117, keratin 5 and E-cadherin) defined three distinct sub-classes amongst EGFR-positive cases, based on the association and differential expression of p53 and Bcl2 (EGFR(+)/p53(-)/bcl2(-), EGFR(+)/p53(+)/bcl2(-) and EGFR(+)/p53(+)/bcl2(+)). Amongst them, only the EGFR(+)/p53+/bcl2(-) sub-class showed significant correlations with grade and TNM parameters. Keratin 5-positive cases were grouped in a special "basal like" group with a particular sub-class rich in CD117(+)/p63(+) cells also highly expressing EGFR. Presence of K5(+)/CD117(+)/p63(+) cells was correlated with all TNM staging parameters defining a particular sub-class with high aggressiveness and particular behavior. Our data sustain EGFR as the key player in the pathogenesis of HNSCCs, but its diagnostic value may be improved by association with other prognostic or therapeutic markers. We herein defined two distinct HNSCCs groups (EGFR(+) and K5(+)) with several sub-classes, identifiable by the additional assessment of p53, Bcl2 and CD117.

Endothelial Cell Proliferation and Vascular Endothelial Growth Factor Expression in Primary Colorectal Cancer and Corresponding Liver Metastases.

BACKGROUND: . Colorectal carcinoma (CRC) is one of the major causes of cancer death worldwide. Data from the literature indicate differences between the proliferation rate of endothelial cells relative to the morphology growth type, possibly due to origin of specimens (autopsy material, surgery fragments) or quantification methods. Vascular endothelial growth factor (VEGF) is a factor that stimulates the proliferation of endothelial cells. It is expressed in more than 90% of cases of metastatic CRC. AIM: The aim of this study was to evaluate the endothelial cell proliferation and VEGF expression in primary tumors and corresponding liver metastases. MATERIALS AND METHODS: Our study included 24 recent biopsies of primary tumors and corresponding liver metastases of CRC cases. CD34/ Ki67 double immunostaining and RNA scope assay for VEGF were performed. RESULTS: In the primary tumors analysis of VEGFmRNA expression indicated no significant correlation with differentiation grade, proliferative and non-proliferative vessels in the intratumoral and peritumoral areas. In contrast, in the corresponding liver metastases, VEGFmRNA expression significantly correlated with the total number of non- proliferative vessels and total number of vessels. CD34/ Ki67 double immunostaining in the cases with poorly differentiated carcinoma indicated a high number of proliferating endothelial cells in the peritumoral area and a low number in the intratumoral area for the primary tumor. Moderately differentiated carcinomas of colon showed no proliferating endothelial cells in the intratumoral area in half of the cases included in the study, for both, primary tumor and liver metastasis. In well differentiated CRCs, in primary tumors, a high proliferation rate of endothelial cells in the intratumoral area and a lower proliferation rate in the peritumoral area were found. A low value was found in corresponding liver metastasis. CONCLUSIONS: The absence of proliferative endothelial cells in half of the cases for the primary tumors and liver metastases in moderately differentiated carcinoma suggest a vascular mimicry phenomenon. The mismatch between the total number of vessels and endothelial proliferation in primary tumors indicate that a functional vascular network is already formed or the existence of some mechanisms influenced by other angiogenic factors.

Mast cells stimulate lymphangiogenesis in the gingiva of patients with periodontal disease.

The presence and distribution of lymphatic vessels and mast cells in the gingiva under normal and pathological conditions have been reported by several studies, but the relationship between them during inflammatory lymphangiogenesis is virtually unknown. The aim of the present study was to investigate the lymphatic microvessel density (LMVD) and mast cell density (MCD) in the gingiva of patients with periodontal disease compared to normal-like gingiva. Gingival punch biopsies from 51 patients with periodontal disease were investigated. MCs and LVs were detected by double-immunohistochemistry, using primary antibodies against mast cell tryptase and D2-40. The inflammatory infiltrate was evaluated on a scale from 0 (absent) to +3 (severe inflammation). MCs and LVs were counted in the same microscopic field for each case at ×200 magnification. We found a significant increase in the number of both MCs and LVs in cases with mild and moderate inflammatory changes, followed by a slight decrease in cases with severe inflammation. We have shown a particular association between MCs and LVs that may support the contribution of MCs to the development of the lymphatic vasculature in inflammatory conditions. MCD correlated with LMVD in all cases with mild and moderate inflammatory changes, but not in cases with severe inflammation. No correlation was found between MCD/LMVD and the density of the inflammatory infiltrate. Our results suggest the potential involvement of MCs in the induction and maintenance of lymphangiogenesis in the gingiva of patients with periodontal disease in the early steps of evolution.

Lymphangiogenesis as a prerequisite in the pathogenesis of lung fibrosis.

Despite increasing knowledge on the cellular and molecular mechanisms involved in pulmonary fibrosis, its therapeutic options are still limited. The study of lymphangiogenesis has contributed to a better understanding of tumor growth and metastasis, with a major impact upon changes in therapeutic strategies and this was followed by the research of lymphatic vessels in other pathological conditions. Some data support the possible role of lymphangiogenesis in the pathogenesis of lung fibrosis. However, at the time of diagnosis for each patient with a fibrotic interstitial lung disease, it is necessary to predict the prognosis and to choose for individual targeted-therapy. Our aim was the characterization of lymphangiogenesis as a useful tool to stratify patients with lung fibrosis. We evaluated the presence, morphology and density of D2-40-positive lymphatic vessels and co-localization of D2-40/Ki67 in pulmonary fibrosis with different degrees of severity and without a specific etiology. Lymphatic vessel density did not correlate with severity grade and ranged between 4.66 to 38.33 vessels/×40 field, with the highest value in degree III of fibrosis. An intense proliferative activity of lymphatic endothelial cells was found in 24% (6 out of 25) of cases. The morphology of lymphatics and the presence of splitting combined with the proliferative activity of endothelial cell pillars suggested two different mechanisms in the formation new lymphatic vessels. Our results support the hypothesis that the activity and ongoing evolution of fibrosis can be predicted through the characterization of lymphangiogenesis but its presence or absence cannot predict the severity of fibrosis.

Interplay between mast cells and lymphatic vessels in different molecular types of breast cancer.

The particularities of lymphangiogenesis in different molecular types of breast cancer are virtually unknown and the contribution of microenvironment to this process has been ever less investigated. In the present study, we evaluated the relationships between lymphatic microvessel density (LMVD), mast cell density (MCD) and the different molecular subtypes of breast cancer. Molecular classification of breast tumors by immunohistochemistry was followed by the detection of mast cells and lymphatic vessels on the same slide by immunohistochemical double-stain method, using the lymphatic endothelial cell marker D2-40 and the mast cell tryptase. Mast cells and lymphatic vessels were simultaneously counted in the tumoral and peritumoral areas and results were compared with the molecular type, grade, lymphovascular invasion and lymph node status. Significant positive correlations were found between peritumoral MCD and LMVD for the luminal type-A breast cancers (p=0.025) and also for basal-like carcinomas (p=0.029). Moreover, a significant positive correlation was found between peritumoral and intratumoral MCD for basal-like carcinomas (p=0.009) and for overall MCD and LMVD. Low or inverse correlations between MCD and LMVD were also observed in other molecular subtypes of breast cancer. Our results strongly support that mast cells in the tumor microenvironment are keyplayers, involved in the development of tumor lymphatic vessels for some molecular subtypes of breast cancer.

Everolimus dual effects of an area vasculosa angiogenesis and lymphangiogenesis.

Recently approved as treatment for astrocytoma, kidney and pancreatic cancer, everolimus acts on tumor cells by inhibiting tumor cell growth and proliferation, as well as by inhibition of angiogenic activity by both direct effects on vascular cell proliferation and indirect effects on growth factor production. The effects of everolimus on early stages of normal vasculogenesis, angiogenesis and lymphangiogenesis are not yet available. We found increased development of intravascular pillars by using area vasculosa of the chick chorioallantoic membrane treated with everolimus. An active lymphangiogenic response was highlighted by the expression of Prospero homeobox protein 1 (Prox1) and podoplanin, together with vascular endothelial growth factor receptor C (Vegf-C) and vascular endothelial growth factor receptor 3 (Vegfr-3) expression on day 4 in the treated group. These findings suggest a potential role of everolimus in the activation of lymphangiogenesis.

Assessement of angiogenesis reveals blood vessel heterogeneity in lung carcinoma.

Despite advances in treatment, the prognosis for lung cancer patients remains poor. Angiogenesis appears to be a promising target for lung cancer therapy; however, the clinical significance of vascular changes are not completely understood. The aim of this study was to evaluate the types and morphology of blood vessels in various lung carcinomas. Using double immunostaining, we investigated 39 biopsies from patients admitted with various histological types of lung carcinoma. Tumor blood vessels were quantified separately for CD34/smooth muscle actin and described as either immature, intermediate or mature. Double immunostaining evaluation of the type of blood vessels in lung carcinomas revealed a marked heterogeneity. The immature and intermediate type of vessels were more common in adenocarcinomas (ADCs) and squamous cell carcinomas (SCCs) of the lung. Small cell lung carcinomas revealed a significant correlation between pathological and immature types of blood vessels. Therefore, quantifying the types of tumor vessels in lung carcinomas may be an important element to improve the results of anti-vascular therapy.

The characterization of PDGFR-alpha and PDGFR-beta expression in malignant non-Hodgkin lymphoma.

PDGF receptors play an important role in tumor progression as being part of a group of receptors that are expressed along the membrane of tumor cells. The aim of this study was to evaluate the PDGF receptor expression in follicular and diffuse forms of non-Hodgkin malignant lymphoma. We evaluated 38 biopsy fragments from patients diagnosed with malignant non-Hodgkin lymphoma. We noticed the distribution of PDGFR-alpha and -beta in tumor cells and the immunoreactivity was quantified as the percentage of positive tumor cells. We noticed the presence of score 3, more than 30% of tumor cells positive, for PDGFR-alpha and PDGFR-beta in 50% and 75% cases of follicular non-Hodgkin lymphoma. For diffuse malignant non-Hodgkin lymphomas, score 3 was noted in 23.52% of cases for PDGFR-alpha and 35.29% of cases for PDGFR-beta. This may represent an important therapeutic target in patients who do not respond to conventional therapy, but further research is needed for a careful evaluation of benefits and side effects of PDGFR inhibitors.

Effects of antibodies to EG-VEGF on angiogenesis in the chick embryo chorioallantoic membrane.

BACKGROUND: Endocrine gland-related vascular endothelial growth factor (EG-VEGF), is an angiogenic factor specifically targeting endothelial cells derived from endocrine tissues. The inhibition of the EG-VEGF/prokineticin receptor pathway could represent a selective antiangiogenic and anticancer strategy. AIM: to evaluate the impact of an antibody to EG-VEGF on the rapidly growing capillary plexus of the chick embryo chorioallantoic membrane (CAM). MATERIALS AND METHODS: The in ovo CAM assay was performed for the humanized EG-VEGF antibody. RESULTS: Hemorrhagic damage was induced in the capillaries, which led to early death of the embryos. Upon morphological staining, there was evidence of vascular disruption and extravasation of red blood cells in the chorion. Signs of vacuolization of the covering epithelium were also observed. CONCLUSION: Blocking endogenous EG-VEGF might represent a valuable approach of impairing or inhibiting angiogenesis in steroidogenic-derived embryonic tissues.

The immunohistochemical expression of endocrine gland-derived-VEGF (EG-VEGF) as a prognostic marker in ovarian cancer.

Ovarian cancer-related angiogenesis is a complex process orchestrated by many positive and negative regulators. Many growth factors are involved in the development of the tumor-associated vasculature, and from these, endocrine gland-derived vascular endothelial growth factor (EG-VEGF) seems to play a crucial role. EG-VEGF is the first organ-specific angiogenic factor and its effects are restricted to the endothelial cells of the endocrine glands. Although EG-VEGF was detected in both normal and neoplastic ovaries, its clinical significance remains controversial. In the present study, we analyzed 30 patients with epithelial ovarian cancer, and the immunohistochemical expression of EG-VEGF was compared with the conventional clinico-pathological parameters of prognosis. Neoplastic cells of the ovarian carcinoma expressed EG-VEGF in 73.33% of the cases, as a cytoplasmic granular product of reaction. We found a strong correlation between the expression of EG-VEGF at protein level and tumor stage, grade, and microscopic type. The expression of EG-VEGF was found in patients with stage III and IV, but not in stage II. The majority of serous adenocarcinoma, half of the cases with clear cell carcinoma and two cases with endometrioid carcinoma showed definite expression in tumor cells. No positive reaction was found in the cases with mucinous carcinoma. Our results showed that EG-VEGF expression is an indicator not only of the advanced stage, but also of ovarian cancer progression. Based on these data, we concluded that EG-VEGF expression in tumor cells of the epithelial ovarian cancer is a good marker of unfavorable prognosis and could be an attractive therapeutic target in patients with advanced-stage tumors, refractory conventional chemotherapy.

Heterogeneity of malignant non-Hodgkin lymphoma-associated blood vessels.

The present study described for the first time a high heterogeneity of blood vessels in non-Hodgkin lymphomas (nHL). The tumor blood vessels were highlighted with CD105÷smooth muscle actin (SMA) and CD34/SMA double immunostaining. For both follicular and diffuse types of lymphomas, more than 85% of CD34/SMA positive vessels were of immature and intermediate type. A percent of 96.54 from CD105/SMA assessed blood vessels were of activated and mature activated types with high expression of CD105 on endothelial cells of newly formed blood vessels. Our results suggest that these types of vessels are potential therapeutic targets for antivascular therapy.

Mast cells contribute to the angiogenesis in non-Hodgkin lymphoma. An immunohistochemical study based on the relationship with microvessel density.

Only few data are available in the literature concerning angiogenesis in hematological malignancies. Non-Hodgkin lymphoma classified on the base of molecular profile is frequently characterized by unpredictable behavior that seems to be related to tumor cells and also to the tumor microenvironment. The tumor microenvironment contains blood vessels and a large variety of cells that can play an important role to the progression of angiogenesis and tumor growth. From these, mast cells have been shown to be a source of angiogenic factors. The aim of this work was to investigated the relationships between mast cells and blood vessels in non-Hodgkin lymphoma and reactive lymphoid tissue from three different anatomical sites. Using double immunostaining method CD34/mast cell tryptase we noticed that mast cell density was significantly lower in the follicular lymphoma than in diffuse type lymphoma. The morphology of vessels, the presence of pillars and splitting suggested that intussusceptions is the main mechanism of angiogenesis. In the cases with primary lymphoma of the spleen, we found few mast cells and a high number of blood vessels. Our data suggest that lymphoma-associated angiogenesis is driven in part by the tumor microenvironment, and particularly, by mast cells. On the other hand, our results support the organ-specific tumor-associated angiogenesis in malignant non-Hodgkin lymphoma.

Platelet-derived growth factor and platelet-derived growth factor receptor-α expression in the normal human thymus and thymoma.

Platelet-derived growth factor (PDGF) and its receptors (PDGFRs) are strongly involved in the normal development of several organs, tumour angiogenesis and malignant progression and metastasis. Few studies concerning their expression, distribution and role in normal and pathological human thymus are available in the literature. The aim of this study has been to analyse the immunohistochemical expression of PDGF and PDGFR-α in prenatal and postnatal normal human thymus and thymomal biopsy specimens. The results demonstrated immunoreactivity to both PDGF and PDGFR-α in all specimens, but the intensity, distribution and number of positive cells were different in normal thymus and thymomas, and also among different tumour types. PDGF and PDGFR-α were weakly expressed in foetal and postnatal humans with a different distribution between cortex and medulla in both blood vessels and epithelial cells, whereas they were overexpressed in thymoma, especially in type B2 and B3, in the tumour epithelial cells. Overall, these data suggest that PDGF and PDGFR-α may be involved in the pathophysiology of the human thymus.

CD105/Ki67 double immunostaining expression in liver metastasis from colon carcinoma.

The liver is the most common and critical site for the development of colon cancer metastases. Tumor angiogenesis in liver metastasis from colon carcinoma is a controversial subject. Liver microenvironment, immunophenotypical and morphological particularities of hepatic vessels are only few aspects, which establish difficulties in quantification of tumor vascularisation from liver metastasis. The aim of this work is to study the distribution of CD105 positive vessels and the proliferation rate of endothelial cells from liver metastasis of colon carcinoma based on double immunostaining CD105/Ki67. In liver metastasis from well-differentiated adenocarcinoma we found a high number of CD105+/Ki67- vessels. On the other hand, in liver metastasis from poorly differentiated adenocarcinoma we noticed rare CD105+/Ki67+ vessels. It is hypothesized that neoangiogenesis of liver metastasis is performed through intussusceptive mechanism rather than sprouting and could be supported by the presence of kissing phenomenon, CD105 positive transcapillary pillars and the absence of endothelial cells proliferation in this vessels. We conclude that in liver metastasis principal mechanism of neovascularisation formation is based on intussusception.