Tatyana Vlaykova

High expression levels of collagenase-1 and stromelysin-1 correlate with shorter disease-free survival in human metastatic melanoma.

Matrix metalloproteinases (MMPs) are proteolytic enzymes capable of degrading extracellular matrix. Their role has been emphasized in tumor invasion, metastasis and tumor‐induced angiogenesis. We studied the expression of collagenase‐1 (MMP‐1), stromelysin‐1 (MMP‐3) and collagenase‐3 (MMP‐13) in 70 melanoma metastases obtained from 56 patients treated with combined chemoimmunotherapy. The patients were divided into 2 groups using a cut‐off point of 0% for MMP‐1 expression and 20% for MMP‐3 expression. We found that patients with MMP‐1 positive metastases (n = 38) had significantly shorter disease‐free survival compared to patients with MMP‐1 negative metastases (n = 18) (median 11.2 vs. 17.0 months, p = 0.0383). The disease‐free survival of patients with high levels of MMP‐3 expression in their metastases (≥20% positive tumor cells, n = 14) was also significantly shorter compared to patients with lower levels of expression (n = 42) (median 5.1 vs. 14.0 months, p = 0.0294). The expression of MMP‐13 did not correlate to survival parameters. We also found that the presence of melanin, a pigment produced by melanocytes, correlated with high expression levels of MMP‐1 (p = 0.0002), MMP‐3 (p < 0.0001) and MMP‐13 (p = 0.0009). The high expression levels of MMP‐13 were also associated with the presence of visceral metastases (p = 0.0284). Our findings suggest that MMP‐1 and ‐3 may have a special role in melanoma metastasis formation and thus they could be used to measure the biological activity of the disease.

Prognostic significance of mast cell number and microvascular density for the survival of patients with primary colorectal cancer

Background and Aim:  The prognostic relevance of tumor‐related angiogenesis and mast cell presence in colorectal cancer remains controversial. The aim of the current study was to assess the mast cell and microvessel densities (MCD and MVD) in the invasive front of colorectal cancers and to determine their prognostic relevance for survival of the patient with colorectal carcinoma.

Prognostic value of tumour vascularity in metastatic melanoma and association of blood vessel density with vascular endothelial growth factor expression.

Tumour angiogenesis is essential for tumour growth and metastasis. Several lines of evidence indicate that vascular endothelial growth factor (VEGF) is a major regulator both of physiological and pathological angiogenesis. In this study we assessed the blood vessel density and VEGF expression of 94 melanoma metastases of 70 patients by immunohistochemistry, utilizing antibodies against human platelet endothelial cell adhesion molecule-1 (PECAM-1, CD31) and VEGF. The number of blood vessels ranged from 4 to 131 vessels/high power field (HPF), with a mean value of 32 vessels/HPF (+/-21) and a median of 29 vessels/ HPF. Survival since diagnosis of the primary disease and from the start of chemoimmunotherapy, as well as the disease-free survival period, was significantly shorter in the high vascularity group of patients compared with the low vascularity group (P< 0.05 and P< 0.01, respectively). A high overall expression of VEGF in the metastatic melanoma samples was observed. The degree of VEGF expression appeared to have a strong association with the blood vessel density (P= 0.017). This study demonstrates the clinical role of tumour vascularity in the prognosis of patients with metastatic melanoma. In addition, the strong association between vascularity and VEGF expression suggests a crucial role for this growth factor in the neovascularization of metastatic melanoma.

Integrin chains beta1 and alphav as prognostic factors in human metastatic melanoma.

The expression pattern of integrin-type cell adhesion receptors is often changed during malignant transformation. In the present work, we studied the prognostic significance of beta1 and alphav integrin chains for survival of patients with metastatic melanoma. The expression levels of beta1 integrin were also compared with those of Bcl-2, an anti-apoptotic protein, the presence of which is associated with treatment response and survival in melanoma. The expression of beta1 and alphav integrins in 68 melanoma metastases obtained from 55 patients treated with combined chemoimmunotherapy was studied by immunohistochemistry using anti-beta1 and anti-alphav antibodies. The patients were divided into two groups (using a cut-off point of >/= 81%) for beta1 integrin expression levels and into three categories (negative/low, median, high) for alphav integrin expression levels. All tumours were positive for beta1 integrin, and the tumours (n = 6) which had the highest alphav score were also strongly positive for beta1 (94%; P = 0.0055). Patients (n = 43) with 80% or less beta1 integrin-positive tumour cells in their samples had a median disease-free survival (DFS) of 17.0 months, and patients (n = 12) with 81% or more beta1 integrin-positive tumour cells had a DFS of only 5.7 months (P = 0.0001). Patients (n = 32) with low alphav integrin expression levels had shorter DFS (median 12.3 months; P = 0.0146) than patients (n = 20) with median expression levels (median 16.7 months; P = 0.0146). However, three patients who had a very strong alphav expression in their tumours had a median DFS of only 1.8 months (P = 0.0146). Median level expression of beta1 integrin was associated with the presence of Bcl-2 in tumour cells (P = 0.0033). Our results suggest that beta1 and alphav integrin chains are independently expressed in metastatic melanoma and may have an effect on the metastatic potential of melanoma cells.

Role of dendritic cells in progression and clinical outcome of colon cancer.

PurposeThe dendritic cells (DCs) are key players in the initiation and regulation of immune responses including antitumor immunity. In the current study, we aimed to elucidate the role of different subtypes of DCs infiltrating the tumor stroma and invasive margin for tumor progression and survival of patients with colon cancer.MethodsThe presence of immature (CD1a- and S100 protein+) and mature (CD83- and HLA-DR+) DCs was evaluated by immunohistochemistry in tissue samples from 145 patients with colon cancer. Patients were dichotomized according to the number of DCs in the tumor stroma and invasive margin, and clinical, histological, and survival data were compared between the two groups of patients.ResultsThe number of the mature CD83+ DCs in the tumor stroma and in the invasive margin significantly correlated with the tumor stage: the lower level of infiltration was found in patients that have advanced tumor stage. The frequency of distant metastases was higher in patients who had lower numbers of immature CD1a+ DCs in tumor stroma and of CD83+ DCs in invasive margin. Patients showing a relatively high number of S100+ DCs in the tumor stroma and HLA-DR+ DCs in the invasive margin had a longer overall survival (p < 0.05). Patients with lower CD83+ DCs infiltration in invasive margin had worse prognosis after surgical therapy compared with those with higher CD83+ DCs infiltration (p = 0.0397).ConclusionsOur results demonstrate that the infiltration of colon cancer with DCs is related with tumor progression and patient prognosis, suggesting a central role for DCs in controlling local antitumor immunity.

Immunohistochemically Detectable Bcl-2 Expression in Metastatic Melanoma: Association with Survival and Treatment Response

Objective: The antiapoptotic protein Bcl-2 is supposed to influence the treatment responsiveness of different malignancies. In the present study the prognostic and predictive significance of Bcl-2 expression for survival and response to an administered therapy was explored in patients with metastatic melanoma. Also, the correlation between Bcl-2 expression and proliferation activity of tumor cells was defined to examine the regulatory role of Bcl-2 in proliferation. Materials and Methods: Sixty metastatic melanomas obtained from patients treated with chemoimmunotherapy were examined by immunohistochemistry with anti-Bcl-2 and anti-Ki-67 (MIB-1) antibodies. Proliferation activity was expressed in percentages as MIB-1 index. Results: The presence of Bcl-2 immunoreactivity was associated with a significantly lower MIB-1 index (p = 0.016), and a longer disease-free survival (p = 0.004). The lack of Bcl-2 expression was related to a higher response rate to therapy in comparison to a diffuse and focal pattern of Bcl-2 expression (p = 0.017). Although the presence of Bcl-2 immunoreactivity as such did not correlate with survival after the initiation of chemoimmunotherapy, the focal Bcl-2 expression pattern was strongly associated with a worse prognosis compared to a diffuse expression or a lack of Bcl-2 staining (p < 0.0001). Conclusions: Our results support the role of Bcl-2 in the regulation of cell proliferation and suggest that an increase of metastatic potential and progression of malignant melanoma is associated with a loss of Bcl-2 expression. The lack of Bcl-2 expression could be a predictor of the response to chemoimmunotherapy, whereas the Bcl-2 expression pattern, possibly indicating the heterogeneity of the tumors, might be a potential prognostic factor for survival after the initiation of therapy.

VASCULARITY AND PROGNOSIS OF METASTATIC MELANOMA

The clinical role of vascularity was examined in metastatic melanoma, analyzing the correlation of the blood vessel density and prognosis. Our study included 51 specimens of metastatic melanoma tissue samples from 31 patients treated with combined chemo‐immunotherapy. PECAM‐1 (CD31) was used for assessing vascularity by immunohistochemical staining. On the basis of blood vessel counts, patients were classified into 2 main groups: low and high vascularity. A higher blood vessel density was found to be associated with shorter survival, estimated from the primary diagnosis of the disease (38 months), compared with patients with low blood vessel counts (68 months). A similar tendency was observed when vascularity was correlated to the survival period after the detection of the first metastases (13 vs. 30 months) and with survival since the initiation of chemo‐immunotherapy (8 vs. 16 months). When vascularity and some common prognostic factors, such as age, sex, DNA ploidy and WHO tumor response, were used for a Cox multivariate analysis, vascularity turned out to be the most significant independent prognostic factor. Our results suggest that counting the blood vessels identified by immunohistochemical staining for the endothelial cell‐specific CD31 is a powerful predictor for prognosis in patients with metastatic melanoma and should be considered when selecting patients for therapy. Int. J. Cancer 74:326‐329, 1997.

High collagenase-1 expression correlates with a favourable chemoimmunotherapy response in human metastatic melanoma.

Matrix metalloproteinases (MMPs) are proteolytic enzymes that can degrade extracellular matrix and thus enhance metastasis. We have studied the expression of two collagenolytic MMPs in 37 samples obtained from 26 patients treated for metastatic melanoma. Interestingly, the samples showed a different expression pattern of collagenase-1 (MMP-1) and collagenase-3 (MMP-13). The samples with high expression levels of MMP-1 (n = 18) were more frequently MMP-13 negative (14 out of 18), whereas those with low expression levels of MMP-1 (n = 15) were predominantly positive for MMP-13 (nine out of 15) (P = 0.027). High expression levels of MMP-1 were associated with a favourable response to chemoimmunotherapy. Responders (n = 13) frequently had intensively MMP-1-expressing metastases (nine out of 13), especially those who achieved a complete response (five out of six). Response failures (n = 7) mainly had metastases with a low intensity of MMP-1 expression (six out of seven) (P = 0.019). There was a tendency towards longer survival among patients with intensively MMP-1-expressing tumours (median 14.3 versus 6.7 months, P = 0.068). The high expression levels of MMP-1 correlated with low MIB-1 (to nuclear antigen Ki-67) (P = 0.019) and positivity for MMP-13 was associated with high MIB-1 expression (P = 0.00048), suggesting that their different expression patterns may affect tumour growth and contribute to differences in patient survival.

Chromogranin A-, serotonin-, synaptophysin- and vascular endothelial growth factor-positive endocrine cells and the prognosis of colorectal cancer: An immunohistochemical and ultrastructural study

Background and Aim:  Endocrine differentiation in colorectal adenocarcinoma has been reported but its significance as a prognostic marker remains uncertain. The aim of the present study was to analyze the prognostic significance of endocrine differentiation in colorectal cancer.

Ile105Val GSTP1 polymorphism and susceptibility to colorectal carcinoma in Bulgarian population.

Background and aimsEtiologically, the sporadic colorectal cancer (CRC) is a complex and multifactorial disease that is linked to both exogenic and endogenic factors. Accumulating evidence indicates that susceptibility to cancers, including CRC, is mediated by genetically determined differences in the effectiveness of detoxification of potential carcinogens. A member of the glutathione-S-transferase (GST) family, GSTP1, is an important candidate for involvement in susceptibility to carcinogen-associated CRC. An A→G transition in exon 5 of the GSTP1 gene resulting in Ile105Val amino acid substitution has been identified. This change leads to alteration in catalytic efficiency of variant enzyme. The aim of the current study was to evaluate the influence of Ile105Val GSTP1 polymorphism on susceptibility to CRC.Materials and methodsThe GSTP1 genotyping was conducted in a case-control study of 80 ethnic Bulgarian CRC patients and 126 unaffected controls using polymerase chain reaction restriction fragment length polymorphism method.ResultsA statistically significant case-control difference in genotype frequencies was observed: 0.69 vs 0.54 for Ile/Ile, 0.22 vs 0.39 for Ile/Val, and 0.09 vs 0.07 for Val/Val (p = 0.049). The odds ratio (OR) for Val/Val was close to 1 (0.96, 95%CI: 0.35–2.66, p = 0.942), whereas the OR for Ile/Val was significantly lower, 0.45 (95%CI: 0.24–0.86, p = 0.016), compared to the referent Ile/Ile genotype. Although a prevalence of the GSTP1 variant allele-containing genotypes (Ile/Val or Val/Val) was found in controls than in patients (OR = 0.53, 95%CI: 0.30–0.96, p = 0.035), the allele frequencies did not show significant difference between cases and controls (p = 0.127).ConclusionsBased on the obtained protective effect of Ile/Val GSTP1 genotype, we could suggest that Ile105Val GSTP1 polymorphism may play some role in susceptibility to CRC.