Person: ŞİMŞEK, MELİH
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Publication Metadata onlyEvaluation of 22 Primary Gastrointestinal Lymphoma Patients(2019-02-01T00:00:00Z) Yildirim, Nilgun; Turkeli, Mehmet; Akdemir, Mehmet Naci; Simsek, MELİH; TEKİN, Salim Başol; ŞİMŞEK, MELİHObjective: Primary gastrointestinal non-hodgkin lymphomas (PGI-NHL) are uncommon diseases with treatment modalities including chemotherapy, surgery, and radiotherapy. Our aim is to analyze the demographic and clinical features and treatment results of PGI-NHL. Publication Metadata onlyAre We Late in the Diagnosis of Malignities Occurring in Solid Organ Transplant Patients? 11 Years- Experience(2016-02-01T00:00:00Z) Turkeli, Mehmet; Simsek, MELİH; Aldemir, Mehmet Naci; Yildirim, Nilgun; ÇANKAYA, Erdem; ERDEMCİ, Burak; BİLİCİ, Mehmet; TEKİN, Salim Başol; Arslan, Sukru; KORKUT, Ercan; ŞİMŞEK, MELİHObjective: Our aim is to evaluate the frequency and characteristics of cancer in the population of patients with solid organ transplant who are under immunosuppressive medication. In this study we aimed to emphasize the importance of early diagnosis of cancer in solid organ transplant recipients. An aging population began to receive solid organ transplantation and survival times prolonged. But this had a cost and new problems came forward. Especially de novo cancers because of immunosuppressive therapy took notice. Risk of malignancy increases after organ transplantation and cancer incidence was about 2.3-3.1% in these patients including skin cancer, lung cancer, malign lymphoma, cervix cancer, kaposi sarcoma, and hepatobiliary cancer. Publication Open AccessDiagnostic performance of apparent diffusion coefficient values for the differentiation of intrahepatic cholangiocarcinoma from gastrointestinal adenocarcinoma liver metastases(2021-12-22T00:00:00Z) Yilmaz, TEMEL FATİH; Gultekin, Mehmet Ali; Turk, Hacı Mehmet; Cesme, Dilek Hacer; Besiroglu, Mehmet; Simsek, Melih; Toprak, Huseyin; Alkan, ALPAY; YILMAZ, TEMEL FATİH; TÜRK, HACI MEHMET; ÇEŞME, DİLEK HACER; ŞİMŞEK, MELİH; ALKAN, ALPAY; TOPRAK, HÜSEYİNBackground: We aimed to investigate whether there is a difference between intrahepatic cholangiocarcinoma (IHCC) and liver metastases of gastrointestinal system (GIS) adenocarcinoma in terms of apparent diffusion coefficient (ADC) values. Patients and methods: From January 2018 to January 2020, we retrospectively examined 64 consecutive patients with liver metastases due to gastrointestinal system adenocarcinomas and 13 consecutive IHCC in our hospital's medical records. After exclusions, fifty-three patients with 53 liver metastases and 10 IHCC were included in our study. We divided the patients into two groups as IHCC and liver metastases of GIS adenocarcinoma. For mean apparent diffusion coefficient (ADCmean) values, the region of interests (ROI) was placed in solid portions of the lesions. ADCmean values of groups were compared. Results: The mean age of IHCC group was 62.50 ± 13.49 and mean age of metastases group was 61.15 ± 9.18. ADCmean values were significantly higher in the IHCC group compared to the metastatic group (p < 0.001). ROC curves method showed high diagnostic accuracy (AUC = 0.879) with cut-off value of < 1178 x 10-6 mm2/s for ADCmean (Sensitivity = 90.57, Specificity = 70.0, positive predictive value [PPV] = 94.1, negative predictive value [NPV] = 58.3) in differentiating adenocarcinoma metastases from IHCC. Conclusions: The present study results suggest that ADC values have a potential role for differentiation between IHCC and GIS adenocarcinoma liver metastases which may be valuable for patient management. Publication Metadata onlyRelationship between 18-FDG-PET/CT and Clinicopathological Features and Pathological Responses in Patients with Locally Advanced Breast Cancers(2019-06-01T00:00:00Z) Yildirim, Nilgun; Simsek, MELİH; Aldemir, Mehmet Naci; BİLİCİ, Mehmet; TEKİN, Salim Başol; ŞİMŞEK, MELİHObjective: We investigated the relationship between the maximum standardized uptake value (SUVmax) of whole-body positron emission tomography/computed tomography (PET/CT) performed before treatment and the demographical and histopathological features in locally advanced breast cancer (LABC), as well as the role of PET/CT in the evaluation of pathological complete response (pCR) after neoadjuvant chemotherapy (NAC). Publication Metadata onlyImmunological Agents Used in Cancer Treatment(2019-02-01T00:00:00Z) Simsek, MELİH; TEKİN, Salim Başol; BİLİCİ, Mehmet; ŞİMŞEK, MELİHImmune checkpoint inhibitors (ICI) are monoclonal antibodies targeting cytotoxic T lymphocyte antigen-4 (CTLA-4), programmed cell death protein-1 (PD-1), or PD-1 ligand (PD-L1). ICI are approved for the treatment of malign melanoma, non-small cell lung cancer, classical Hodgkin lymphoma, head and neck squamous cell carcinoma, urothelial carcinoma, and renal cell carcinoma. They can lead to long-term anti-tumor responses by deactivating the brake mechanism in the immune system. Ipilimumab, tremelimumab, pembrolizumab, nivolumab, atezolizumab, durvalumab, and avelumab are examples of ICI. CTLA-4 is a brake mechanism in immune response. Ipilimumab and tremelimumab are antibodies against CTLA-4. PD-1 is another important immune checkpoint co-inhibitor receptor that is expressed by activated T cells in the peripheral tissue. As a result of blockage of the PD-1/PD-L1 pathway, local tumor-specific immune response augments, and long-term tumor control can be achieved. In recent years, ICI are approved for the treatment of various malignities. They may be responsible for specific toxicities called immune-related adverse events (irAEs). irAEs are a consequence infiltration of normal tissues by activated T lymphocytes that are responsible for autoimmunity. Corticosteroids and anti-tumor necrosis factor agents, such as infliximab and mycophenolate mofetil, are effective in the treatment of irAEs. Immune checkpoint inhibition with monoclonal antibodies against CTLA-4 and/or PD-1/PD-L1 by single agent or combination treatments became a new option in various solid tumors. However, ICI have unique adverse events, and these adverse events should be considered in any new onset clinical situation and should be managed properly. Future prospective randomized clinical trials will clarify recent questions. Publication Open AccessBreast Cancer Patients with Brain Metastases: A Cross-Sectional Study.(2022-08-19T00:00:00Z) Simsek, MELİH; Aliyev, Altay; Baydas, Tuba; Besiroglu, Mehmet; Demir, Tarik; Shbair, Abdallah Tm; Seker, Mesut; Turk, H Mehmet; ŞİMŞEK, MELİH; TÜRK, HACI MEHMETThe prognosis of breast cancer patients with brain metastasis is poor. It was aimed to define the clinicopathological features of breast cancer patients with brain metastases and to determine the risk factors and survival outcomes associated with brain metastasis. This is a single-center, retrospective, cross-sectional study. A total number of 127 patients diagnosed with breast cancer and who developed brain metastasis between January 2011 and March 2021 were retrospectively analyzed. The survival and clinicopathological data of these patients according to 4 biological subtypes were evaluated (luminal A, luminal B, HER-2 overexpressing, and triple-negative). The median overall survival for all patients was 45.6 months. The median time from the diagnosis of breast cancer to the occurrence of brain metastasis was 29.7 months, and the median survival time after brain metastasis was 7.2 months. The time from the diagnosis of breast cancer to brain metastasis development was significantly shorter in HER-2 overexpressing and triple-negative subtypes than in luminal A and B subtypes. The median time from breast cancer diagnosis to brain metastasis was 33.5 months in luminal A, 40.6 months in luminal B, 16.8 months in HER-2 overexpressing, and 22.8 months in the triple-negative groups (p=0.003). We found the worst median survival after brain metastasis in the triple-negative group with 3.5 months. Early and close surveillance of high-risk patients may help early diagnosis of brain metastasis and may provide to perform effective treatments leading to longer overall survival times for this patient population. Publication Metadata onlyMide kanserli hastaların demografik özelliklerinin sağ kalıma etkisi(2022-05-01T00:00:00Z) Karadeniz, Andaç; Bilici, Mehmet; Şimşek, Melih; ŞİMŞEK, MELİH Publication Metadata onlyThe effect of adenosine triphosphate on sunitinib-induced cardiac injury in rats(2020-08-01T00:00:00Z) KARA, ALİ VEYSEL; Aldemir, Mehmet Şerif; Simsek, MELİH; ÖZÇİÇEK, FATİH; MAMMADOV, RENAD; YAZICI, GÜLCE NAZ; SUNAR, MUKADDER; COŞKUN, REŞİT; GÜLABOĞLU, Mine; SÜLEYMAN, HALİS; ŞİMŞEK, MELİHIn this study, we aimed to show the effect of adenosine 5 --triphosphate (ATP) on sunitinib-induced cardiac injury in rats. The rats (n = 30) were divided equally into three groups as sunitinib group (SG), sunitinib plus ATP group (SAG), and healthy group (HG); 2 mg/kg ATP was injected intraperitoneally (ip) to the SAG group. Same volume normal saline as solvent was administered ip to the other two groups. After 1 h, 25 mg/kg sunitinib was applied orally via catheter to stomach in the SAG and SG groups. This procedure was repeated once daily for 5 weeks. At the end of this period, all animals were sacrificed and their cardiac tissue was removed. Malondialdehyde (MDA), total glutathione (tGSH), tumor necrosis factor alpha (TNF-alpha), and nuclear factor kappa B (NF-kappa B) levels in rats- cardiac tissues and troponin I (Tp-I) levels in rats- blood samples were evaluated. Histopathological analysis was also performed in cardiac tissues of the animals. MDA, TNF-alpha, NF-kappa B, and Tp-I levels were higher in the SG group compared to the SAG and HG groups (p < 0.001). tGSH levels of the SG group were lower than the SAG and HG groups (p < 0.001). The structure and morphology of cardiac muscle fibers and blood vessels were normal in the control group. In the SG group, obvious cardiac muscle tissue damage with dilated myofibers, locally atrophic myofibers, and congested blood vessels were observed. In the SAG group, marked amelioration in these findings was observed. We showed this for the first time that ATP administration exerts a protective effect against cardiac effects of sunitinib. Publication Metadata onlyEfficacy and tolerability of weekly docetaxel, cisplatin, and 5-fluorouracil for locally advanced or metastatic gastric cancer patients with ECOG performance scores of 1 and 2.(2015-01-01T00:00:00Z) Turkeli, Mehmet; Aldemir, Mehmet Naci; Cayir, Kerim; Simsek, MELİH; Bilici, Mehmet; Tekin, Salim Basol; Yildirim, Nilgun; Bilen, Nurhan; Makas, Ibrahim; ŞİMŞEK, MELİH Publication Open AccessEfficacy and safety profile of COVID-19 vaccine in cancer patients: a prospective, multicenter cohort study(2022-01-01T00:00:00Z) YASİN, Ayşe İrem; Aydin, Sabin Goktas; SÜMBÜL, BİLGE; KORAL, LOKMAN; ŞİMŞEK, MELİH; Geredeli, Caglayan; Ozturk, Akin; Perkin, Perihan; Demirtas, Derya; Erdemoglu, Engin; HACIBEKİROĞLU, İLHAN; Cakir, Emre; Tanrikulu, Eda; Coban, Ezgi; Ozcelik, Melike; Celik, Sinemis; Teker, Fatih; AKSOY, ASUDE; Firat, Sedat T.; Tekin, Omer; Kalkan, Ziya; Turken, Orhan; Oven, Bala B.; Dane, Faysal; Bilici, Ahmet; Isikdogan, Abdurrahman; ŞEKER, Mesut; TÜRK, HACI MEHMET; Gumus, Mahmut; YASİN, AYŞE İREM; SÜMBÜL, BİLGE; ŞİMŞEK, MELİH; ŞEKER, MESUT; TÜRK, HACI MEHMETAim: To compare the seropositivity rate of cancer patients with noncancer controls after inactive SARS-CoV-2 vaccination and evaluate the factors affecting seropositivity. Method: Spike IgG antibodies against SARS-CoV-2 were measured in blood samples of 776 cancer patients and 715 noncancer volunteers. An IgG level ≥50 AU/ml is accepted as seropositive. Results: The seropositivity rate was 85.2% in the patient group and 97.5% in the control group. The seropositivity rate and antibody levels were significantly lower in the patient group (p < 0.001). Age and chemotherapy were associated with lower seropositivity in cancer patients (p < 0.001). Conclusion: This study highlighted the efficacy and safety of the inactivated vaccine in cancer patients.