Erythropoietin accelerates tumor growth through increase of erythropoietin receptor (EpoR) as well as by the stimulation of angiogenesis in DLD-1 and Ht-29 xenografts.

Anemia is a relatively common symptom coexisting with colorectal carcinoma. Besides having a positive impact on hematological parameters, erythropoietin (Epo) has the serious adverse effect of promoting the neoplastic process. The role of Epo in colon cancer has not been clearly shown. The aim of this study was to assess the effects of Epo therapy on colorectal carcinoma cells both in in vitro and in animal models. Human colon adenocarcinoma cells DLD-1 and Ht-29 were cultured in medium with Epo beta in normoxia. Cell proliferation was measured with an automated cell counter. Expression of erythropoietin receptor (EpoR) mRNA, Akt mRNA, and their proteins were assessed by RT-PCR and confocal microscopy, respectively. Nude mice were inoculated with adenocarcinoma cells and treated with a therapeutic dose of Epo. Expression of EpoR, VEGF, Flt-1 and CD31 was evaluated in xenograft tumors. We identified that Epo through EpoR activates Akt, which promotes colon cancer cell growth and proliferation. Epo, and high levels of phosphorylated EpoR, directly accelerates tumor growth through its proliferative and proangiogenic effects. This study demonstrated that Epo had enhanced carcinogenesis through increase of EpoR and Flt-1 expression, and thereby contributed to tumor development. These results suggest that both EpoR-positive and EpoR-negative cancer cells could be regulated by exogenous Epo. However, an increased response to erythropoietin was observed in the EpoR-positive cells. Thus, erythropoietin increases the risk of tumor progression in colon cancer and should not be used to treat anemia in this type of cancer.

Expression of insulin-like growth factor receptor type 1 correlate with lymphatic metastases in human gastric cancer.

Most patients with gastric cancer are diagnosed at advanced clinical stages with a high frequency of lymph node metastasis. It is very important to find novel factors for the early diagnostic and prognostic evaluation of gastric cancer. It has been shown that IGF-1R activates mitotic division and inhibits apoptosis of cancer cells through the activation of signaling MAP/ERK and PI3K/Akt-1 pathways. IGF-1R plays a role in cell transformation and maintenance of the phenotype in modified cells. Moreover, an IGF-1 receptor effect influences the processes of adhesion, migration, invasion and metastasis of tumor cells. The aim of the study was to assess the expression of IGF-1R in gastric carcinoma in correlation with selected anatomo-clinical parameters. The study enrolled a group of 49 patients treated surgically for gastric cancer. 28 patients had no lymph node metastases. The expression of the studied proteins was assessed using the immunohistochemical method. We found that the expression of IGF-1R in gastric cancer is associated with lymph node metastasis (p < 0.001), is correlated with worse prognosis and high histological malignancy grade, and is an independent predictor of survival in patients with gastric cancer (p < 0.001). IGF-1R may play an important role in tumor growth and metastasis via the lymphatic pathway.

Diagnostic significance of TIMP-1 level in serum and its immunohistochemical expression in colorectal cancer patients.

Tissue inhibitor of metalloproteinase-1 (TIMP-1) inhibits the ability of cancer cells to metastasize, but it can also stimulate cancer development. The aim of this study was to assess the level of TIMP-1 in serum and its expression in patients with colorectal cancer (CRC). The study group consisted of 43 patients diagnosed with colorectal cancer and 24 healthy volunteers. The level of TIMP-1 was assessed by the ELISA method while the expression of this protein was performed immunohistochemically. The concentration of TIMP-1 in the sera of colorectal cancer patients was significantly higher than in the healthy control group (p = 0.004). Higher level of TIMP-1 in the sera correlated with female gender (p = 0.045), tumor location in colon (p = 0.016), poorly differentiated tumor (p = 0.034) and higher platelet count in whole blood (p < 0.004). A positive reaction of the protein in cancer cells was observed in 31 cases and was found to correlate negatively with its reaction in peritumoral stroma (p < 0.001). According to this study, TIMP-1 protein may play an important role in cancer development. The assessment of this molecule in serum and tissue can be useful at the time of diagnosis and can help us to understand the nature of colorectal pathogenesis.

Expression of phosphatase of regenerating liver-3 (PRL-3) in endometrioid cancer and lymph nodes metastases.

PURPOSE: We identify the expression of PRL-3 in primary endometrioid endometrial cancer and metastases in relation to the clinicopathological characteristics. MATERIAL/METHODS: The study involved 30 patients with type I endometrial cancer. Twelve of them were diagnosed with metastases in various localization of abdomen. The PRL-3 expression was evaluated on the basis of immunohistochemistry results by the use of monoclonal antibody anti-PRL3 clone 3B6. RESULTS: The intensity of PRL-3 expression in correlation with tumor stage was statistically significant (p = 0.024). The strongest reaction was noted in cases classified as a 1a and 1b stage defined by FIGO. The strength of PRL-3 expression is significantly associated with the degree of histological tumor grade (p = 0.035). CONCLUSIONS: The strong expression of PRL-3 in the primary tumor that was significantly correlated with the grade and clinical stage suggest that PTP4A3 participates in the process of endometrial carcinogenesis.

Matrix metalloproteinase 2 (MMP-2) and their tissue inhibitor 2 (TIMP-2) in gastric cancer patients.

BACKGROUND: Matrix metalloproteinase 2 (MMP-2) is able to degrade type IV collagen and its activity is mostly regulated by tissue inhibitor of matrix metalloproteinase 2 (TIMP-2). These proteins might play a role in tumor progression, including gastric cancer (GC). METHODS: The study included 108 individuals, GC patients and healthy subjects. Serum levels of all analyzed markers were evaluated by the immunological methods, while immunohistochemistry was used to assess the expression of these proteins in GC, interstitial inflammatory cells and normal tissues. RESULTS: The percentage of positive reactions of MMP-2 and TIMP-2 was higher in GC and inflammatory cells compared to normal tissue, while serum levels of these proteins were statistically lower in GC patients in comparison to healthy subjects. There was a significant positive correlation between TIMP-2 immunoreactivity in inflammatory cells and the presence of lymph node metastasis. Area under ROC curve (AUC) for TIMP-2 was higher than MMP-2, while serum MMP-2 was an independent prognostic factor of GC patients' survival. CONCLUSION: Our findings suggest that TIMP-2 seems to be a predictor of tumor progression, especially for nodal involvement, whereas serum MMP-2 might be useful as an independent prognostic factor of patients' survival.

Immunohistochemical assessment of apoptosis-associated proteins: p53, Bcl-xL, Bax and Bak in gastric cancer cells in correlation with clinical and pathomorphological factors.

PURPOSE: The p53 protein as well as Bcl-2 family proteins such as Bax, Bak and Bcl-xL regulate apoptosis. The study objective was to analyze the expression of p53, Bak, Bcl-xL and Bax in gastric cancer and in healthy gastric mucosa. MATERIAL AND METHODS: The study group consisted of 66 patients with gastric cancer, treated surgically in II Department of General and Gastroenterological Surgery, Medical University of Bialystok. The expression of the studied proteins was assessed using the immunohistochemical method. RESULTS: Significant differences were found in the expressions of the studied proteins as compared to healthy gastric mucosa. The expressions of p53 and Bax were significantly higher (70% vs 13% and 50% vs 13%), whereas those of Bak and Bcl-xL significantly lower (18% vs 83% and 74% vs 97%) in cancer cells than in normal mucosa (p<0.001). Significant differences were also noted in the expressions of Bax and Bcl-xL in relation to histological type. In the intestinal type (Lauren I), the expressions of Bax and Bcl-xL were higher as compared to the diffuse type (Lauren II) (93% vs 43% and 91% vs 43%). Simultaneously, correlations were noted between changes in the expression of Bax vs Bcl-xL and Bak. High expression of Bax showed a positive correlation with reduced Bak and Bcl-xL (p<0.05). Moreover, positive expression of p53 caused poorer distant survival of patients (p<0.05). CONCLUSION: Our study concluded that disturbances in the expression of p53, Bax, Bcl-xL and Bak proteins are associated with their involvement in the process of carcinogenesis in the stomach. It is suggesting that they might appeared in the early phase of carcinogenesis.

Immunohistochemical assessment of PRL-3 (PTP4A3) expression in tumor buds, invasion front, central region of tumor and metastases of colorectal cancer.

PURPOSE: The aim of the study was to evaluate immunohistochemical expression of PRL-3 protein tumor buds, invasion front, central region of tumor and metastases of colorectal cancer. MATERIAL/METHODS: The PRL-3 expression was analyzed in 103 colorectal carcinoma patients, using the immunohistochemical method with a monoclonal antibody 3B6 anti-PRL-3 (Attogen Biomedical Research, USA). RESULTS: Positive reaction for PRL-3 was observed in 36.9% of cases in the central region of tumor, in 64.3% in the invasion front, and in as many as 81.4% in buds (present in 70/103 cases), in 100% in metastases to local lymph nodes, in 100% in metastases to the liver and in 97.1% in metastases to the lungs. The findings indicate that cancer cells obtain this protein already in the early stages of metastasizing. PRL-3 is present not only in metastases to local lymph nodes but also to distant organs. It is likely that PRL-3 protein takes part in the initiation of metastasizing of cancer cells. Also the presence of lymph and blood vessel invasion was found only to correlate with increased percentage of patients with strong PRL-3 expression in tumor buds (p=0.046). CONCLUSION: Our results may suggests the participation of PRL-3 protein as a marker of the presence of colorectal cancer metastasis to the lymph nodes and distant metastases, which is independent of parameters such as gender and age of the patients, tumor location, histological type and grade of histological malignancy and stage of tumor.