A comparative urinary proteomic and metabolomic analysis between renal aa amyloidosis and membranous nephropathy with clinicopathologic correlations.

Urinary omics has become a powerful tool for elucidating pathophysiology of glomerular diseases. However, no urinary omics analysis has been performed yet on renal AA amyloidosis. Here, we performed a comparative urine proteomic and metabolomic analysis between recently diagnosed renal AA amyloidosis (AA) and membranous nephropathy (MN) patients. Urine samples of 22 (8 AA, 8 MN and 6 healthy control) patients were analyzed with nLC-MS/MS and GC/MS for proteomic and metabolomic studies, respectively. Pathological specimens were scored for glomerulosclerosis and tubulointerstitial fibrosis grades. Functional enrichment analysis between AA and control groups showed enrichment in cell adhesion related sub-domains. Uromodulin (UMOD) was lower, whereas ribonuclease 1 (RNase1) and α-1-microglobulin/bikunin precursor (AMBP) were higher in AA compared to MN group. Correlations were demonstrated between UMOD-proteinuria (r = -0.48, p = 0.03) and AMBP-eGFR (r = -0.69, p = 0.003) variables. Metabolomic analysis showed myo-inositol and urate were higher in AA compared to MN group. A positive correlation was detected between RNase1 and urate independent of eGFR values (r = 0.63, p = 0.01). Enrichment in cell adhesion related domains suggested a possible increased urinary shear stress due to amyloid fibrils. UMOD, AMBP and myo-inositol were related with tubulointerstitial damage, whereas RNase1 and urate were believed to be related with systemic inflammation in AA amyloidosis. SIGNIFICANCE: Urinary omics studies have become a standard tool for biomarker studies. However, no urinary omics analysis has been performed yet on renal AA amyloidosis. Here, we performed a comparative urinary omics analysis between recently diagnosed renal AA amyloidosis (AA), membranous nephropathy (MN) patients and healthy controls. Pathological specimens were scored with glomerulosclerosis (G) and tubulointerstitial fibrosis (IF) grades to consolidate the results of the omics studies and correlation analyzes. Functional enrichment analysis showed enrichment in cell adhesion related sub-domains due to downregulation of cadherins; which could be related with increased urinary shear stress due to amyloid deposition and disruption of tissue micro-architecture. In comparative proteomic analyzes UMOD was lower, whereas RNase1 and AMBP were higher in AA compared to MN group. Whereas in metabolomic analyzes; myo-inositol, urate and maltose were higher in AA compared to MN group. Correlations were demonstrated between UMOD-proteinuria (r = -0.48, p = 0.03), AMBP-eGFR (r = -0.69, p = 0.003) and between RNase1-Urate independent of eGFR values (r = 0.63, p = 0.01). This study is the first comprehensive urinary omics analysis focusing on renal AA Amyloidosis to the best of our knowledge. Based on physiologic roles and clinicopathologic correlations of the molecules; UMOD, AMBP and myo-inositol were related with tubulointerstitial damage, whereas RNase1 and urate were believed to be increased with systemic inflammation and endothelial damage in AA amyloidosis.

Occurrence and severity of myasthenic crisis in an unselected Turkish cohort of patients with myasthenia gravis.

Myasthenia gravis (MG) is a disorder of the neuromuscular junction that can deteriorate into myasthenic crisis, involving weakness of bulbar and respiratory muscles. In this study, we describe the clinical manifestations of myasthenic crisis, identify risk factors, and examine treatments and outcomes. All 95 patients with generalized MG treated at our center during the last 10 years were included in this retrospective study. We collected data from the patients' records, including clinical follow-ups, muscle antibodies, thymic status, and treatments. The characteristics of patients who did and did not experience myasthenic crisis were compared. Features of all myasthenic crises were also assessed. Twelve patients (13%) developed myasthenic crisis during the observation period. Men were more often affected at older ages. Seven patients experienced multiple myasthenic crises. Thymoma increased the risk of a crisis, whereas thymic hyperplasia decreased the risk. Myasthenic crises were more common in the summer months. No patients died during a myasthenic crisis. Risk factors for myasthenic crisis were thymoma, older age, MuSK antibodies, and previous crises. Individualized and active immunosuppressive treatment and optimal intensive care during crises provide a good outcome for patients with generalized MG.

IVIg-induced headache: prospective study of a large cohort with neurological disorders.

BACKGROUND: Intravenous immune globulin (IVIg) is frequently used in some neurological diseases and is also the first-line therapy in Guillain-Barré syndrome, chronic inflammatory demyelinating polyneuropathy, and multifocal motor neuropathy. We aimed to evaluate the frequency and characteristics of headaches, which is one of the most common side effects of IVIg treatment. METHODS: Patients who received IVIg treatment for neurological diseases were prospectively enrolled in 23 centers. Firstly, the characteristics of patients with and without IVIg-induced headaches were analyzed statistically. Then, patients with IVIg-induced headaches were classified into three subgroups determined by their history: no primary headache, tension-type headache (TTH), and migraine. RESULTS: A total of 464 patients (214 women) and 1548 IVIg infusions were enrolled between January and August 2022. The frequency of IVIg-related headaches was 27.37% (127/464). A binary logistic regression analysis performed with significant clinical features disclosed that female sex and fatigue as a side effect were statistically more common in the IVIg-induced headache group. IVIg-related headache duration was long and affected daily living activities more in patients with migraine compared to no primary headache and TTH groups (p = 0.01, respectively). CONCLUSION: Headache is more likely to occur in female patients receiving IVIg and those who develop fatigue as a side effect during the infusion. Clinicians' awareness of IVIg-related headache characteristics, especially in patients with migraine, may increase treatment compliance.

Cell cycle-dependent palmitoylation of protocadherin 7 by ZDHHC5 promotes successful cytokinesis.

Cell division requires dramatic reorganization of the cell cortex, which is primarily driven by the actomyosin network. We previously reported that protocadherin 7 (PCDH7) gets enriched at the cell surface during mitosis, which is required to build up the full mitotic rounding pressure. Here, we report that PCDH7 interacts with and is palmitoylated by the palmitoyltransferase, ZDHHC5. PCDH7 and ZDHHC5 colocalize at the mitotic cell surface and translocate to the cleavage furrow during cytokinesis. The localization of PCDH7 depends on the palmitoylation activity of ZDHHC5. Silencing PCDH7 increases the percentage of multinucleated cells and the duration of mitosis. Loss of PCDH7 expression correlates with reduced levels of active RhoA and phospho-myosin at the cleavage furrow. This work uncovers a palmitoylation-dependent translocation mechanism for PCDH7, which contributes to the reorganization of the cortical cytoskeleton during cell division.

Plasma proteomics identify potential severity biomarkers from COVID-19 associated network.

PURPOSE: Coronavirus disease 2019 (COVID-19) continues to threaten public health globally. Severe acute respiratory coronavirus type 2 (SARS-CoV-2) infection-dependent alterations in the host cell signaling network may unveil potential target proteins and pathways for therapeutic strategies. In this study, we aim to define early severity biomarkers and monitor altered pathways in the course of SARS-CoV-2 infection. EXPERIMENTAL DESIGN: We systematically analyzed plasma proteomes of COVID-19 patients from Turkey by using mass spectrometry. Different severity grades (moderate, severe, and critical) and periods of disease (early, inflammatory, and recovery) are monitored. Significant alterations in protein expressions are used to reconstruct the COVID-19 associated network that was further extended to connect viral and host proteins. RESULTS: Across all COVID-19 patients, 111 differentially expressed proteins were found, of which 28 proteins were unique to our study mainly enriching in immunoglobulin production. By monitoring different severity grades and periods of disease, CLEC3B, MST1, and ITIH2 were identified as potential early predictors of COVID-19 severity. Most importantly, we extended the COVID-19 associated network with viral proteins and showed the connectedness of viral proteins with human proteins. The most connected viral protein ORF8, which has a role in immune evasion, targets many host proteins tightly connected to the deregulated human plasma proteins. CONCLUSIONS AND CLINICAL RELEVANCE: Plasma proteomes from critical patients are intrinsically clustered in a distinct group than severe and moderate patients. Importantly, we did not recover any grouping based on the infection period, suggesting their distinct proteome even in the recovery phase. The new potential early severity markers can be further studied for their value in the clinics to monitor COVID-19 prognosis. Beyond the list of plasma proteins, our disease-associated network unravels altered pathways, and the possible therapeutic targets in SARS-CoV-2 infection by connecting human and viral proteins. Follow-up studies on the disease associated network that we propose here will be useful to determine molecular details of viral perturbation and to address how the infection affects human physiology.

AF10 (MLLT10) prevents somatic cell reprogramming through regulation of DOT1L-mediated H3K79 methylation.

BACKGROUND: The histone H3 lysine 79 (H3K79) methyltransferase DOT1L is a key chromatin-based barrier to somatic cell reprogramming. However, the mechanisms by which DOT1L safeguards cell identity and somatic-specific transcriptional programs remain unknown. RESULTS: We employed a proteomic approach using proximity-based labeling to identify DOT1L-interacting proteins and investigated their effects on reprogramming. Among DOT1L interactors, suppression of AF10 (MLLT10) via RNA interference or CRISPR/Cas9, significantly increases reprogramming efficiency. In somatic cells and induced pluripotent stem cells (iPSCs) higher order H3K79 methylation is dependent on AF10 expression. In AF10 knock-out cells, re-expression wild-type AF10, but not a DOT1L binding-impaired mutant, rescues overall H3K79 methylation and reduces reprogramming efficiency. Transcriptomic analyses during reprogramming show that AF10 suppression results in downregulation of fibroblast-specific genes and accelerates the activation of pluripotency-associated genes. CONCLUSIONS: Our findings establish AF10 as a novel barrier to reprogramming by regulating H3K79 methylation and thereby sheds light on the mechanism by which cell identity is maintained in somatic cells.

Gene variants of TCF7L2 are histopathologically important in colorectal cancers but do not have direct association with MYC expression.

Rapidly accumulating preclinical and clinical studies have helped us to unveil underlying mechanisms of colorectal cancer development and progression. Deregulated signaling pathways play instrumental role in carcinogenesis, drug resistance and metastasis. Wnt signaling cascade has attracted considerable attention in colorectal cancer as many ground-breaking researches have highlighted central role of Wnt pathway in pathogenesis of colorectal cancer. T-Cell Transcription Factors (TCFs) have been shown to work synchronously with ß-catenin to fuel colorectal cancer development and progression. Chromatin immuno-precipitation coupled with high-throughput sequencing (ChIP-Seq) data sets has deepened our knowledge about critical role of risk-associated SNPs. Increasingly it is being reported that many risk-associated SNPs are located within binding sites for transcription factors and consequently risk status of these SNPs may modify binding pattern of transcriptional factors and thus rewire the transcriptional regulation. DNA was extracted from peripheral blood samples of 117 colorectal cancer patients and 127 healthy subjects. TCF7L2 variants (rs6983267, rs7903146) were examined by the PCR-RFLP method. Tumor and the surrounding tissues were dissected from 37 CRC patients and RNA isolation was performed. The gene expression of c-myc was determined by RT-PCR. T allele carriage of rs6983267 variant was found to be associated with CRC (p=0.042). TT genotype of rs7903146 was associated with late tumor stage (T3+T4) (p=0.037) and presence of mucinous component (p=0.031). TTCT haplotype was found to be statistically higher in CRC compared to the control group (p=0.007). There was no statistically significant difference in c-myc gene expression. TCF7L2 gene variants may play an important role in histopathologic aspects associated with CRC and it is independent of c-myc gene expression.

Proteomics in Cell Division.

Cell division requires a coordinated action of the cell cycle machinery, cytoskeletal elements, chromosomes, and membranes. Cell division studies have greatly benefitted from the mass spectrometry (MS)-based proteomic approaches for probing the biochemistry of highly dynamic complexes and their coordination with each other as a cell progresses into division. In this review, the authors first summarize a wide-range of proteomic studies that focus on the identification of sub-cellular components/protein complexes of the cell division machinery including kinetochores, mitotic spindle, midzone, and centrosomes. The authors also highlight MS-based large-scale analyses of the cellular components that are largely understudied during cell division such as the cell surface and lipids. Then, the authors focus on posttranslational modification analyses, especially phosphorylation and the resulting crosstalk with other modifications as a cell undergoes cell division. Combining proteomic approaches that probe the biochemistry of cell division components with functional genomic assays will lead to breakthroughs toward a systems-level understanding of cell division.

Relationship of CTLA4 and CD28 polymorphisms with lung involvement, HRCT findings and pulmonary function tests in Turkish patients with ankylosing spondylitis.

BACKGROUND AND AIMS: Ankylosing spondylitis (AS) is a multisystem disorder with ocular, pulmonary, and cardiovascular involvement. The incidence of pulmonary involvement varies from 1 to 52%. Abnormal T-cell function-derived immune responses are involved in AS pathogenesis. Numerous genes such as CTLA4 and CD28 control T-cell functions. In this study, we aimed to address the relationship between CTLA4 and CD28 polymorphisms and lung involvement in Turkish patients with AS. METHODS: A cross-sectional evaluation of 80 healthy and 89 AS subjects with no active infection or malignancy was performed to determine the relationship between pulmonary involvement and CTLA4 and CD28 gene polymorphisms. All patients were assessed for clinical, radiological, and spirometric findings. Descriptive statistics, chi-square tests, and independent-sample t-tests were used for statistical analyses. RESULTS: All patients with the CD28 CC genotype (n = 4) had abnormal HRCT, but it was not significant (p = 0.47). All of the normal HRCT patients have CD 28 T alleles. In addition to this data ; 4 patients who have not any T alleles have abnormal HRCT finding. It was significant and was considered that T genotype have protective effect (p= 0,047) on radiologic involvement but no other association was found between CTLA4 and CD28 gene polymorphism with respect to pulmonary function tests (PFT), diffusion capacity, and clinical characteristics in the Turkish patients with AS. CONCLUSION: Our results suggest a possible association of CTLA4 and CD28 variants with AS pulmonary involvement. Furthermore, these results may lead to the development of new therapeutic agents to control more aggressive forms of the disease. However, further studies are needed in larger populations.

Expression of miR-373 and its predicted target genes E-cadherin and CD44 in patients with laryngeal squamous cell carcinoma.

Laryngeal squamous cell carcinoma (LSCC) is a genomically complex disease that is difficult to target, and efforts have been made to identify new treatment strategies and   molecular markers that might stratify patients and individualize options for treatment. miR-373 has diametrically opposed roles in different stages and types of cancers. miR-373 has been suggested to quantitatively control E-cadherin and CD44 expression. We studied the expression of miR-373, E-cadherin and CD44 in laryngeal squamous cell carcinoma and evaluated the association between the disease and clinical characteristics of patients. Tumor tissues were collected from 24 laryngeal cancer patients. Adjacent normal tissue samples were also obtained as controls. After RNA isolation, we assessed the miR-373, E-cadherin and CD44 levels. As endogenous controls, we used the small RNA U6 and GAPDH TaqMan® to normalize the levels of expression of miR-373, E-cadherin and CD44. The fold change in the expression of the genes in larynx tumor and control tissues was calculated using the 2-ΔΔCT method. miR-373 was significantly upregulated in seventeen tumor samples compared to controls. However, the expression levels of both E-cadherin and CD44 mRNA were found to be significantly downregulated in tumor versus control regions (p=0.026 and p=0.005, respectively). We did not find any significant difference in the expression levels of miR-373, E-cadherin or CD44 and cancer risk factors. miR-373, E-cadherin and CD44 may be involved in the etiopathogenesis of laryngeal cancer. It can be suggested that E-cadherin and CD44 are functional targets of miR-373, but we need further studies to investigate this hypothesis.

LGALS3 and AXIN1 gene variants playing role in the Wnt/ ß-catenin signaling pathway are associated with mucinous component and tumor size in colorectal cancer.

The Wnt pathway alterations have been identified in colorectal and many other cancer types. It has been reported that galectin-3 (which is encoded by the LGALS3 gene) alters the signaling mechanism in the Wnt/ ß-catenin pathway by binding to ß-catenin in colon and other cancers. AXIN1 is mainly responsible for the assembly of the ß-catenin destruction complex in the Wnt pathway. This study investigated the relationship of rs4644 and rs4652 variants of the LGALS3 gene and rs214250 variants of the AXIN1 gene to histopathological and clinical properties. Our study included a total of 236 patients, of whom 119 had colorectal cancer (42 women, 77 men) and 117 were healthy controls. Polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) and allele-specific oligonucleotide (ASO) PCR methods were used. In addition, the serum galectin-3 level was studied with the enzyme-linked immunosorbent assay (ELISA) method. For the rs4644 variant of the LGALS3 gene, the CC genotype a mucinous component was significantly more common than those without a mucinous component (p=0.026). C allele frequency of the rs214250 variant of the AXIN1 gene was significantly correlated to tumor size in the advanced tumor stage (p=0.022). The CCAACT haplotype was more common in colorectal cancer patients (p=0.022). Serum galectin-3 level was higher in the patient group compared to the control group (5.9± 0.69 ng/ml vs. 0.79±0.01 ng/ml; p<0.001). In conclusion, variants of LGALS3 and AXIN1 genes affect tumor sizes and the mucinous component via Wnt/ ß-catenin pathway in the pathogenesis of colorectal cancer.

Genetic variants in the tumor necrosis factor-related apoptosis-inducing ligand and death receptor genes contribute to susceptibility to bladder cancer.

AIM: The aim of this study was to evaluate the role of polymorphisms of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and death receptor (DR4) genes in bladder cancer susceptibility in a Turkish population. MATERIALS AND METHODS: The study group included 91 bladder cancer patients, while the control group comprised 139 individuals with no evidence of malignancy. Gene polymorphisms of TRAIL C1595T (rs1131580) and DR4 C626G (rs4871857) were genotyped by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis. RESULTS: The frequency of the TRAIL 1595 TT genotype was significantly lower in patients with bladder cancer compared to controls (p<0.001; odds ratios [OR]=0.143; 95% confidence interval [CI]=0.045-0.454). A significantly increased risk for developing bladder cancer was found for the group bearing a C allele for TRAIL C1595T polymorphism (p<0.001; OR=1.256; 95% CI=1.138-1.386). The observed genotype and allele frequencies of DR4 626 C/G in all groups were in agreement with the Hardy-Weinberg equilibrium (p=0.540). However, the frequency of DR4 GG genotype was found to be 2.1-fold increased in the bladder cancer patients with high-grade tumor, when compared to those having low-grade tumor (p=0.036). Additionally, combined genotype analysis showed that the frequency of TRAILCT-DR4GG was significantly higher in patients with bladder cancer in comparison with those of controls (p=0.037; OR=2.240; 95% CI=1.138-1.386). CONCLUSIONS: Our study provides new evidence that TRAIL 1595 C allele may be used as a low-penetrant risk factor for bladder cancer development in a Turkish population. Otherwise, gene-gene interaction analysis revealed that the DR4GG genotype may have a predominant effect on the increased risk of bladder cancer over the TRAIL CT genotype.

Restoring TRAIL mediated signaling in ovarian cancer cells.

Ovarian cancer has emerged as a multifaceted and genomically complex disease. Genetic/epigenetic mutations, suppression of tumor suppressors, overexpression of oncogenes, rewiring of intracellular signaling cascades and loss of apoptosis are some of the deeply studied mechanisms. In vitro and in vivo studies have highlighted different molecular mechanisms that regulate tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) mediated apoptosis in ovarian cancer. In this review, we bring to limelight, expansion in understanding systematical characterization of ovarian cancer cells has led to the rapid development of new drugs and treatments to target negative regulators of TRAIL mediated signaling pathway. Wide ranging synthetic and natural agents have been shown to stimulate mRNA and protein expression of death receptors. This review is compartmentalized into programmed cell death protein 4, platelet-derived growth factor signaling and miRNA control of TRAIL mediated signaling to ovarian cancer. Mapatumumab and PRO95780 have been tested for efficacy against ovarian cancer. Use of high-throughput screening assays will aid in dissecting the heterogeneity of this disease and increasing a long-term survival which might be achieved by translating rapidly accumulating information obtained from molecular and cellular studies to clinic researches.

Association between laryngeal squamous cell carcinoma and polymorphisms in tumor necrosis factor related apoptosis induce ligand (TRAIL), TRAIL receptor and sTRAIL levels.

The laryngeal squamous cell carcinoma (LSCC) is one of the most common malignant tumors occurring in the head and neck. Tumor necrosis factor related apoptosis induce ligand (TRAIL) and TRAIL-receptors (DR4, DR5, DcR1, DcR2) are known as important members of TRAIL-mediated biochemical signaling pathway. Associations between polymorphisms in these genes and clinicopathological characteristics of human laryngeal carcinoma are not well defined. This study therefore aimed to investigate a possible relationship among the TRAIL and TRAIL-DR4 polymorphisms and sTRAIL levels in the risk or progression of LSCC. A total of 99 patients with laryngeal cancer and 120 healthy subjects were enrolled in the study. DR4 C626G and TRAIL 1595 C/T genotypes were determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis and sTRAIL levels were measured by ELISA. There were significant differences in the distribution of DR4 C626G genotypes and frequencies of the alleles between laryngeal cancer patients and controls (p<0.001) but not in TRAIL 1595 C/T. We found the increased frequency of the DR4 C626G homozygote CC genotype in patients than in controls (p<0.001). Haplotype analysis revealed that there was also a statistically significant relationship between TRAIL and TRAIL-DR4 polymorphisms and laryngeal cancer. Serum sTRAIL levels in the laryngeal patients with CC genotype who had advanced tumour stage were lower than those of patients with early tumor stage (p=0.014). Our findings suggest that DR4 C626G genotypes and sTRAIL levels might be associated with progression of laryngeal cancer in the Turkish population.

Cyclin D1 gene G870A variants and primary brain tumors.

Alterations of cyclin D1, one of the main regulators of the cell cycle, are known to be involved in various cancers. The CCDN1 G870A polymorphism causes production of a truncated variant with a shorter half-life and thus thought to impact the regulatory effect of CCDN1. The aim of the present study was to contribute to existing results to help to determine the prognostic value of this specific gene variant and evaluate the role of CCDN1 G870A polymorphism in brain cancer susceptibility. A Turkish study group including 99 patients with primary brain tumors and 155 healthy controls were examined. Genotypes were determined by polymerase chain reaction-restriction fragment length polymorphism analysis. The CCDN1 genotype frequencies in meningioma, glioma and control cases were not significantly different (p>0.05). No significant association was detected according to clinical parameters or tumor characteristics; however, a higher frequency of AG genotype was recorded within patients with astrocytic or oligoastrocytic tumors. A significant association between AG genotype and gliobilastoma multiforme (GBM) was recorded within the patients with glial tumors (p value=0.048 OR: 1.87 CI% 1.010-3.463). According to tumor characteristics, no statistically significant difference was detected within astrocytic, oligoasltrocytic tumors and oligodentrioglias. However, patients with astrocytic astrocytic or oligoastrocytic tumors showed a higher frequency of AG genotype (50%) when compared to those with oligodendrioglial tumors (27.3%). Our results indicate a possible relation between GBM formation and CCDN1 genotype.

Possible relation between the NOS3 gene GLU298ASP polymorphism and bladder cancer in Turkey.

Endothelial nitric oxide synthase (eNOS), encoded by the NOS3 gene, has been suggested to play an important role in uncontrolled cell growth in several cancer types. The objective of this study was to evaluate the role of the NOS3 Glu298Asp polymorphism in bladder cancer susceptibility in a Turkish population. We determined the genotypes of 66 bladder cancer cases and 88 healthy controls. Genotypes were determined by polymerase chain reaction-restriction fragment length polymorphism analysis. A significant association for NOS3 Glu298Asp heterozygotes genotypes and T allely were found between healthy controls and bladder cancer, respectively (p<0.001: p=0.002). There were no significant associations between any genotypes and the stage, grade, and histological type of bladder cancer. Our study suggested an increased risk role of NOS3 GT genotype in bladder cancer susceptibility in our Turkish population.

CK2 enzyme affinity against c-myc 424-434 substrate in human lung cancer tissue.

CK2 is a serine threonine kinase that participates in a variety of cellular processes with more than 300 defined substrates. This critical enzyme is known to be upregulated in cancers, but the role of this upregulation in carcinogenesis is not yet fully understood but c-myc, one of the defined CK2 substrates, is a well-known proto- oncogene that is normally essential in developmental process but is also involved in tumor development. We evaluated the optimal enzyme and substrate concentrations for CK2 activity in both neoplastic and non-neoplastic human lung tissues using the c-myc 424-434 peptide (EQKLISEEDL) as a substrate. The activities measured for the neoplastic tissue were 600-750 U/mg protein while those for the control tissue was in the range of 650-800 U/ mg. Km value for c-myc peptide was determined as 0.33 µM in non-neoplastic tissue and 0.18 µM in neoplastic tissue. In this study, we did not observe an increased activity in the neoplastic tissue when compared with the non-neoplastic lung tissue, but we recorded two times higher affinity for c-myc 424-434 in cancer tissue. Considering the metabolic position of c-myc 424-434, our results suggest that phosphorylation by CK2 may be important in dimerization and thus it might affect the regulation of c-myc in cancer tissues.