Anja Kafka - Academia.edu (original) (raw)

Papers by Anja Kafka

Research paper thumbnail of Optimal amplification conditions for D16S3399 polymorphic STS axin-1 gene marker

ABSTRACT We investigated D16S3399 marker and affirmed it as a highly polymorphic marker useful fo... more ABSTRACT We investigated D16S3399 marker and affirmed it as a highly polymorphic marker useful for the analysis of the human axin-1 gene. Axin-1 acts as a tumor suppressor gene and its protein is an inhibitor of the Wnt signaling pathway. We report on heterozygosity status, alleles frequency observed in a prelimirary group of Croatian subjects and the optimal amplification conditions of D16S3399 marker. The amplified CA repeat was confirmed by direct sequencing.

Research paper thumbnail of Genetic changes observed in a case of adult pilocytic astrocytoma revealed by array CGH analysis

Molecular Cytogenetics, 2014

Background: A palette of copy number changes in a case of adult pilocytic astrocytoma analyzed by... more Background: A palette of copy number changes in a case of adult pilocytic astrocytoma analyzed by Array Comparative Genomic Hybridization (aCGH) is presented. Pilocytic astrocytomas are specific gliomas that are benign and biologically distinct and the molecular mechanisms responsible for their development remain unexplained. The aCGH was performed using SurePrint G3 Human CGH microarrays 4 × 180 K (Agilent Technologies). To ascertain whether some of the aberrations were of constitutive nature, we also analyzed the blood sample from the same patient.

Research paper thumbnail of Molecular alterations of E-cadherin and beta-catenin in brain metastases

Frontiers in bioscience (Elite edition), 2011

The molecular mechanisms and candidate genes involved in metastasis to the brain need elucidation... more The molecular mechanisms and candidate genes involved in metastasis to the brain need elucidation. In the present study brain metastases were analyzed regarding changes of E-cadherin (CDH1) and beta-catenin (CTNNB1). Loss of heterozygosity (LOH) of the CDH1 gene was detected in 42.2% of samples. The highest frequency of LOHs was observed in metastases from primary sites of lung adenocarcinoma and small cell lung cancer. Metastases from breast and colon demonstrated changes in 55.6% and 50% of cases. Downregulation of E-cadherin protein was observed in 83% of samples. Only 21.1% of samples with E-cadherin LOH had beta-catenin located in the nucleus. Image analysis showed that the quantities of E-cadherin and beta-catenin were significantly positively correlated (P = 0.008). Changes of E-cadherin were frequent in brain metastases that we investigated. Lack of mutations of beta-catenin, the fact that it was not frequently found in the nucleus and the positive correlation between the two proteins may suggest that the break-up of adherens junctions, and not the activation of wnt signaling, is responsible for metastasis formation.

Research paper thumbnail of Replication error-positive samples found in pheochromocytomas

In vivo (Athens, Greece)

Background: Adenomatous polyposis coli, (APC) and E-cadherin (CDH1) tumor suppressor genes were i... more Background: Adenomatous polyposis coli, (APC) and E-cadherin (CDH1) tumor suppressor genes were investigated in human pheochromocytoma. Both genes are components of adherens junctions, but are also involved in wnt signalling in which one of the target molecules is c-myc protein. Materials and Methods: Fifteen sporadic pheochromocytomas were tested for gene instability by PCR/loss of heterozygosity. Detection of c-myc protein was performed using immunohistochemistry. Results: One sample with allelic imbalance of the APC gene and one with allelic imbalance of the CDH1 gene were found. Interestingly, another type of genomic instability was detected -replication error-positive samples (RER+). Four out of 13 heterozygous samples were RER-positive (30.8%). The instability is the result of impaired cellular mismatch repair. Immunohistochemistry showed increased levels of c-myc in comparison to normal adrenal tissue. Conclusion: Our results suggest that microsatellite genetic instabilities of the E-cadherin gene have a role in pheochromocytoma development and progression. Detected instability indicates that mismatch repair may be targeted in pheochromocytoma. Increased expression of c-myc protein as well as allelic imbalances of APC and CDH 1 genes suggest that the wnt signalling pathway may have a role in this malignancy.

Research paper thumbnail of Loss of heterozygosity of CDKN2A (p16INK4a) and RB1 tumor suppressor genes in testicular germ cell tumors

Radiology and Oncology, 2010

Background. Testicular germ cell tumors (TGCTs) are the most frequent malignances in young adult ... more Background. Testicular germ cell tumors (TGCTs) are the most frequent malignances in young adult men. The two main histological forms, seminomas and nonseminomas, differ biologically and clinically. pRB protein and its immediate upstream regulator p16INK4a are involved in the RB pathway which is deregulated in most TGCTs. The objective of this study was to evaluate the occurrence of loss of heterozygosity (LOH) of the CDKN2A (p16INK4a) and RB1 tumor suppressor genes in TGCTs.

Research paper thumbnail of Expression of Secreted Frizzled-Related Protein 1 and 3, T-cell Factor 1 and Lymphoid Enhancer Factor 1 in Clear Cell Renal Cell Carcinoma

Pathology & Oncology Research, 2013

Frequency and mortality of renal cell carcinoma (RCC) are increasing for decades. However, the mo... more Frequency and mortality of renal cell carcinoma (RCC) are increasing for decades. However, the molecular background of RCC tumorigenesis is still poorly understood. In current study we investigated the expression of TCF/LEF and SFRP family members (SFRP1 and SFRP3) to gain a better understanding of biological signaling pathways responsible for epidemiology and clinical parameters of clear cell RCC (cRCC). Thirty-six pairs of paraffinembedded clear cRCC and adjacent nontumoral tissues samples using immunohistochemistry (IHC) were analyzed and compared with corresponding clinicopathological parameters. Immunohistochemistry indicated statistically significant decreased SFRP3 expression in tumor tissues but no consistency in SFRP1 expression in analyzed normal and tumor tissue. The TCF1 expression level was significantly weaker in normal tissue compared to tumor samples while LEF1 protein levels were significantly weaker in tumor tissue. To our knowledge, this is the first report on analysis of the expression of transcription factors TCF1 and LEF1 in clear cell renal cell carcinoma and their comparison with Wnt signal pathway antagonists belonging to SFRP family.

Research paper thumbnail of Epithelial-to-mesenchymal transition: possible role in meningiomas

Frontiers in Bioscience, 2012

Epithelial-to-mesenchimal transition (EMT) is a process involved in invasion and metastasis of tu... more Epithelial-to-mesenchimal transition (EMT) is a process involved in invasion and metastasis of tumors. The occurrence of EMT during tumor progression resembles the developmental scenario and sheds light on important mechanisms for the initial step of metastasis - invasion where noninvasive tumor cells acquire motility and ultimately disseminate to distant organs. The hallmark of EMT is the loss of expression of the cell-cell adhesion molecule E-cadherin. The numerous reports by many authors as well as our own results indicate that E-cadherin plays a role in CNS tumors - meningiomas. Our studies showed that 73 % of meningiomas had downregulation of E-cadherin. Moreover, loss of heterozygosity of E-cadherin was observed in 32 % of meningiomas. Bound to E-cadherin in adherens junctions is beta-catenin, whose translocation to the nucleus is yet another molecular event involved in EMT. In our study beta-catenin was progressively upregulated from meningothelial to atypical, while 60 % of anaplastic meningiomas showed upregulation and nuclear localization of the protein. The elucidation of molecular mechanisms that govern EMT will offer new approaches and targets to restrain metastasis.

Research paper thumbnail of Genetic changes of the E‐cadherin and APC tumour suppressor genes in clear cell renal cell carcinoma

Pathology, 2004

Aims: The roles of tumour suppressor genes: adenomatous polyposis coli (APC) and E-cadherin (CDH1... more Aims: The roles of tumour suppressor genes: adenomatous polyposis coli (APC) and E-cadherin (CDH1) were investigated in clear cell renal cell carcinoma. Methods: Forty-five human clear cell renal cell carcinomas were tested for APC gene instability by polymerase chain reaction/loss of heterozygosity using the restriction fragment length polymorphism method. E-cadherin gene was analysed by PCR amplification of tetranucleotide marker (D16S752) and the alleles were visualised by PAGE/silver staining. Results: The overall proportion of loss of heterozygosity of the APC gene was 37.5% (9/24). D16S752 marker linked to E-cadherin gene (informativeness 91%) revealed three samples with loss of heterozygosity (7.5%). Interestingly, replication error phenotype was detected in 9.1% of clear cell renal cell carcinoma samples. Multivariate statistical analysis of samples informative for both APC and E-cadherin genes showed that, in this data set, loss of heterozygosity of the APC gene is correlated with advanced age and more severe TNM stages. Genetic changes of the E-cadherin gene, on the other hand, appear to be correlated with younger age groups and less severe TNM stages. Conclusions: Our results suggest that alterations, both in APC and E-cadherin genes, are involved in the evolution and progression of clear cell renal cell carcinoma. Microsatellite genetic instability of the E-cadherin gene indicates that another cellular mechanism, mismatch repair, may also be targeted in this malignancy.

Research paper thumbnail of Genetic changes of the E-cadherin and APC tumour suppressor genes in clear cell renal cell carcinoma

Pathology, 2004

Aims: The roles of tumour suppressor genes: adenomatous polyposis coli (APC) and E-cadherin (CDH1... more Aims: The roles of tumour suppressor genes: adenomatous polyposis coli (APC) and E-cadherin (CDH1) were investigated in clear cell renal cell carcinoma. Methods: Forty-five human clear cell renal cell carcinomas were tested for APC gene instability by polymerase chain reaction/loss of heterozygosity using the restriction fragment length polymorphism method. E-cadherin gene was analysed by PCR amplification of tetranucleotide marker (D16S752) and the alleles were visualised by PAGE/silver staining. Results: The overall proportion of loss of heterozygosity of the APC gene was 37.5% (9/24). D16S752 marker linked to E-cadherin gene (informativeness 91%) revealed three samples with loss of heterozygosity (7.5%). Interestingly, replication error phenotype was detected in 9.1% of clear cell renal cell carcinoma samples. Multivariate statistical analysis of samples informative for both APC and E-cadherin genes showed that, in this data set, loss of heterozygosity of the APC gene is correlated with advanced age and more severe TNM stages. Genetic changes of the E-cadherin gene, on the other hand, appear to be correlated with younger age groups and less severe TNM stages. Conclusions: Our results suggest that alterations, both in APC and E-cadherin genes, are involved in the evolution and progression of clear cell renal cell carcinoma. Microsatellite genetic instability of the E-cadherin gene indicates that another cellular mechanism, mismatch repair, may also be targeted in this malignancy.

Research paper thumbnail of Optimal amplification conditions for D16S3399 polymorphic STS axin-1 gene marker

ABSTRACT We investigated D16S3399 marker and affirmed it as a highly polymorphic marker useful fo... more ABSTRACT We investigated D16S3399 marker and affirmed it as a highly polymorphic marker useful for the analysis of the human axin-1 gene. Axin-1 acts as a tumor suppressor gene and its protein is an inhibitor of the Wnt signaling pathway. We report on heterozygosity status, alleles frequency observed in a prelimirary group of Croatian subjects and the optimal amplification conditions of D16S3399 marker. The amplified CA repeat was confirmed by direct sequencing.

Research paper thumbnail of Genetic changes observed in a case of adult pilocytic astrocytoma revealed by array CGH analysis

Molecular Cytogenetics, 2014

Background: A palette of copy number changes in a case of adult pilocytic astrocytoma analyzed by... more Background: A palette of copy number changes in a case of adult pilocytic astrocytoma analyzed by Array Comparative Genomic Hybridization (aCGH) is presented. Pilocytic astrocytomas are specific gliomas that are benign and biologically distinct and the molecular mechanisms responsible for their development remain unexplained. The aCGH was performed using SurePrint G3 Human CGH microarrays 4 × 180 K (Agilent Technologies). To ascertain whether some of the aberrations were of constitutive nature, we also analyzed the blood sample from the same patient.

Research paper thumbnail of Molecular alterations of E-cadherin and beta-catenin in brain metastases

Frontiers in bioscience (Elite edition), 2011

The molecular mechanisms and candidate genes involved in metastasis to the brain need elucidation... more The molecular mechanisms and candidate genes involved in metastasis to the brain need elucidation. In the present study brain metastases were analyzed regarding changes of E-cadherin (CDH1) and beta-catenin (CTNNB1). Loss of heterozygosity (LOH) of the CDH1 gene was detected in 42.2% of samples. The highest frequency of LOHs was observed in metastases from primary sites of lung adenocarcinoma and small cell lung cancer. Metastases from breast and colon demonstrated changes in 55.6% and 50% of cases. Downregulation of E-cadherin protein was observed in 83% of samples. Only 21.1% of samples with E-cadherin LOH had beta-catenin located in the nucleus. Image analysis showed that the quantities of E-cadherin and beta-catenin were significantly positively correlated (P = 0.008). Changes of E-cadherin were frequent in brain metastases that we investigated. Lack of mutations of beta-catenin, the fact that it was not frequently found in the nucleus and the positive correlation between the two proteins may suggest that the break-up of adherens junctions, and not the activation of wnt signaling, is responsible for metastasis formation.

Research paper thumbnail of Replication error-positive samples found in pheochromocytomas

In vivo (Athens, Greece)

Background: Adenomatous polyposis coli, (APC) and E-cadherin (CDH1) tumor suppressor genes were i... more Background: Adenomatous polyposis coli, (APC) and E-cadherin (CDH1) tumor suppressor genes were investigated in human pheochromocytoma. Both genes are components of adherens junctions, but are also involved in wnt signalling in which one of the target molecules is c-myc protein. Materials and Methods: Fifteen sporadic pheochromocytomas were tested for gene instability by PCR/loss of heterozygosity. Detection of c-myc protein was performed using immunohistochemistry. Results: One sample with allelic imbalance of the APC gene and one with allelic imbalance of the CDH1 gene were found. Interestingly, another type of genomic instability was detected -replication error-positive samples (RER+). Four out of 13 heterozygous samples were RER-positive (30.8%). The instability is the result of impaired cellular mismatch repair. Immunohistochemistry showed increased levels of c-myc in comparison to normal adrenal tissue. Conclusion: Our results suggest that microsatellite genetic instabilities of the E-cadherin gene have a role in pheochromocytoma development and progression. Detected instability indicates that mismatch repair may be targeted in pheochromocytoma. Increased expression of c-myc protein as well as allelic imbalances of APC and CDH 1 genes suggest that the wnt signalling pathway may have a role in this malignancy.

Research paper thumbnail of Loss of heterozygosity of CDKN2A (p16INK4a) and RB1 tumor suppressor genes in testicular germ cell tumors

Radiology and Oncology, 2010

Background. Testicular germ cell tumors (TGCTs) are the most frequent malignances in young adult ... more Background. Testicular germ cell tumors (TGCTs) are the most frequent malignances in young adult men. The two main histological forms, seminomas and nonseminomas, differ biologically and clinically. pRB protein and its immediate upstream regulator p16INK4a are involved in the RB pathway which is deregulated in most TGCTs. The objective of this study was to evaluate the occurrence of loss of heterozygosity (LOH) of the CDKN2A (p16INK4a) and RB1 tumor suppressor genes in TGCTs.

Research paper thumbnail of Expression of Secreted Frizzled-Related Protein 1 and 3, T-cell Factor 1 and Lymphoid Enhancer Factor 1 in Clear Cell Renal Cell Carcinoma

Pathology & Oncology Research, 2013

Frequency and mortality of renal cell carcinoma (RCC) are increasing for decades. However, the mo... more Frequency and mortality of renal cell carcinoma (RCC) are increasing for decades. However, the molecular background of RCC tumorigenesis is still poorly understood. In current study we investigated the expression of TCF/LEF and SFRP family members (SFRP1 and SFRP3) to gain a better understanding of biological signaling pathways responsible for epidemiology and clinical parameters of clear cell RCC (cRCC). Thirty-six pairs of paraffinembedded clear cRCC and adjacent nontumoral tissues samples using immunohistochemistry (IHC) were analyzed and compared with corresponding clinicopathological parameters. Immunohistochemistry indicated statistically significant decreased SFRP3 expression in tumor tissues but no consistency in SFRP1 expression in analyzed normal and tumor tissue. The TCF1 expression level was significantly weaker in normal tissue compared to tumor samples while LEF1 protein levels were significantly weaker in tumor tissue. To our knowledge, this is the first report on analysis of the expression of transcription factors TCF1 and LEF1 in clear cell renal cell carcinoma and their comparison with Wnt signal pathway antagonists belonging to SFRP family.

Research paper thumbnail of Epithelial-to-mesenchymal transition: possible role in meningiomas

Frontiers in Bioscience, 2012

Epithelial-to-mesenchimal transition (EMT) is a process involved in invasion and metastasis of tu... more Epithelial-to-mesenchimal transition (EMT) is a process involved in invasion and metastasis of tumors. The occurrence of EMT during tumor progression resembles the developmental scenario and sheds light on important mechanisms for the initial step of metastasis - invasion where noninvasive tumor cells acquire motility and ultimately disseminate to distant organs. The hallmark of EMT is the loss of expression of the cell-cell adhesion molecule E-cadherin. The numerous reports by many authors as well as our own results indicate that E-cadherin plays a role in CNS tumors - meningiomas. Our studies showed that 73 % of meningiomas had downregulation of E-cadherin. Moreover, loss of heterozygosity of E-cadherin was observed in 32 % of meningiomas. Bound to E-cadherin in adherens junctions is beta-catenin, whose translocation to the nucleus is yet another molecular event involved in EMT. In our study beta-catenin was progressively upregulated from meningothelial to atypical, while 60 % of anaplastic meningiomas showed upregulation and nuclear localization of the protein. The elucidation of molecular mechanisms that govern EMT will offer new approaches and targets to restrain metastasis.

Research paper thumbnail of Genetic changes of the E‐cadherin and APC tumour suppressor genes in clear cell renal cell carcinoma

Pathology, 2004

Aims: The roles of tumour suppressor genes: adenomatous polyposis coli (APC) and E-cadherin (CDH1... more Aims: The roles of tumour suppressor genes: adenomatous polyposis coli (APC) and E-cadherin (CDH1) were investigated in clear cell renal cell carcinoma. Methods: Forty-five human clear cell renal cell carcinomas were tested for APC gene instability by polymerase chain reaction/loss of heterozygosity using the restriction fragment length polymorphism method. E-cadherin gene was analysed by PCR amplification of tetranucleotide marker (D16S752) and the alleles were visualised by PAGE/silver staining. Results: The overall proportion of loss of heterozygosity of the APC gene was 37.5% (9/24). D16S752 marker linked to E-cadherin gene (informativeness 91%) revealed three samples with loss of heterozygosity (7.5%). Interestingly, replication error phenotype was detected in 9.1% of clear cell renal cell carcinoma samples. Multivariate statistical analysis of samples informative for both APC and E-cadherin genes showed that, in this data set, loss of heterozygosity of the APC gene is correlated with advanced age and more severe TNM stages. Genetic changes of the E-cadherin gene, on the other hand, appear to be correlated with younger age groups and less severe TNM stages. Conclusions: Our results suggest that alterations, both in APC and E-cadherin genes, are involved in the evolution and progression of clear cell renal cell carcinoma. Microsatellite genetic instability of the E-cadherin gene indicates that another cellular mechanism, mismatch repair, may also be targeted in this malignancy.

Research paper thumbnail of Genetic changes of the E-cadherin and APC tumour suppressor genes in clear cell renal cell carcinoma

Pathology, 2004

Aims: The roles of tumour suppressor genes: adenomatous polyposis coli (APC) and E-cadherin (CDH1... more Aims: The roles of tumour suppressor genes: adenomatous polyposis coli (APC) and E-cadherin (CDH1) were investigated in clear cell renal cell carcinoma. Methods: Forty-five human clear cell renal cell carcinomas were tested for APC gene instability by polymerase chain reaction/loss of heterozygosity using the restriction fragment length polymorphism method. E-cadherin gene was analysed by PCR amplification of tetranucleotide marker (D16S752) and the alleles were visualised by PAGE/silver staining. Results: The overall proportion of loss of heterozygosity of the APC gene was 37.5% (9/24). D16S752 marker linked to E-cadherin gene (informativeness 91%) revealed three samples with loss of heterozygosity (7.5%). Interestingly, replication error phenotype was detected in 9.1% of clear cell renal cell carcinoma samples. Multivariate statistical analysis of samples informative for both APC and E-cadherin genes showed that, in this data set, loss of heterozygosity of the APC gene is correlated with advanced age and more severe TNM stages. Genetic changes of the E-cadherin gene, on the other hand, appear to be correlated with younger age groups and less severe TNM stages. Conclusions: Our results suggest that alterations, both in APC and E-cadherin genes, are involved in the evolution and progression of clear cell renal cell carcinoma. Microsatellite genetic instability of the E-cadherin gene indicates that another cellular mechanism, mismatch repair, may also be targeted in this malignancy.