Lutfi Ozkan

Radioprotection by two phenolic compounds: Chlorogenic and quinic acid, on X-ray induced DNA damage in human blood lymphocytes in vitro

The present study was designed to determine the radioprotective effect of two phytochemicals, namely, quinic acid and chlorogenic acid, against X-ray irradiation-induced genomic instability in non-tumorigenic human blood lymphocytes. The protective ability of two phenolic acids against radiation-induced DNA damage was assessed using the alkaline comet assay in human blood lymphocytes isolated from two healthy human donors. A Siemens Mevatron MD2 (Siemens AG, USA, 1994) linear accelerator was used for irradiation. The results of the alkaline comet assay revealed that quinic acid and chlorogenic acid decreased the DNA damage induced by X-ray irradiation and provided a significant radioprotective effect. Quinic acid decreased the presence of irradiation-induced DNA damage by 5.99-53.57% and chlorogenic acid by 4.49-48.15%, as determined by the alkaline comet assay. The results show that quinic acid and chlorogenic acid may act as radioprotective compounds. Future studies should focus on determining the mechanism by which these phenolic acids provide radioprotection.

The relationship between genetic susceptibility to head and neck cancer with the expression of common fragile sites

Numerous studies have recently been conducted to investigate genetic mechanisms in cancer causes and pathogenesis. Some of these studies have shown that there were certain specific chromosomal defects in normal cells of cancer patients and in their first‐degree relatives. It was suggested that these individuals were susceptible to cancer development when compared with people without these defects.

Factors influencing axillary node metastasis in breast cancer.

Aims and Background The status of the axillary lymph nodes at the time of diagnosis has been accepted as one of the most important prognostic factors for the overall and disease-free survival of patients with breast cancer. The aim of our study was to determine which factors influence axillary node involvement in invasive breast cancer. Methods The data presented here were obtained from 344 patients who were treated for invasive breast cancer at the Department of Radiation Oncology, Uludag University Medical College, Bursa, Turkey. Possible prognostic factors were categorized as patient related and tumor related. The Mann-Whitney U test was used for univariate analysis and logistic regression was used for multivariate analysis. Results In univariate analysis, a familial cancer history (P = 0.0042), age <40 years (P = 0.0276), higher T stage (P <0.0000), nipple involvement (P = 0.0345), skin involvement (P = 0.0270), perineural invasion (P = 0.0231), and lymphatic vessel invasion (P <0.0000) were correlated with increased axillary node involvement. A higher incidence of ≥4 involved lymph nodes was associated with higher T stage (P = 0.0004), nipple involvement (P = 0.0292), presence of an extensive intraductal component (P = 0.0023), skin involvement (P = 0.0008), perineural invasion (P = 0.0523), and lymphatic vessel invasion (P <0.0000) in univariate analysis. In multivariate analysis, age <40 years (P = 0.0454), cancer history within the family (P = 0.0024), higher T stage (P = 0.0339), lymphatic vessel invasion (P = 0.0003), and perineural invasion (P = 0.0408) were found to be independent factors for axillary lymph node positivity. Age <40 years (P = 0.0221), perineural invasion (P = 0.0408), and an extensive intraductal component (P = 0.0132) were associated with an increased incidence of ≥4 involved nodes in the logistic regression analysis. In patients with breast cancer, the incidence of axillary lymph node involvement was independently influenced by age <40 years, presence of cancer history within the family, higher T stage, lymphatic vessel invasion, and perineural invasion. Conclusions In conclusion, absence of familial cancer history, presence of lymphatic vessel invasion, higher T stage, and age below 40 years independently increased the risk of axillary node involvement. Presence of perineural invasion and lymphatic vessel invasion, age below 40, and an extensive intraductal component of more than 25% independently affected the risk of having ≥4 nodes involved. Patients characterized by these factors may be classified into a higher risk group for nodal involvement, but more data are needed to define factors that can help in the decision-making regarding the omission of axillary treatment.

Carcinoma originating from aberrant breast tissue. A case report and review of the literature

Carcinoma arising from ectopic breast tissue, either supernumerary breast or aberrant breast tissue, is extremely rare. Carcinoma occurs more frequently in the ectopic breast tissue of the axilla than in extra-axillary ectopic breast tissue. Here we report a case of an invasive lobular carcinoma arising from extra-axillary ectopic breast tissue and presenting as a subcutaneous nodule.

Radio-protective effect of cinnamic acid, a phenolic phytochemical, on genomic instability induced by X-rays in human blood lymphocytes in vitro.

The present study was designed to determine the protective activity of cinnamic acid against induction by X-rays of genomic instability in normal human blood lymphocytes. This radio-protective activity was assessed by use of the cytokinesis-block micronucleus test and the alkaline comet assay, with human blood lymphocytes isolated from two healthy donors. A Siemens Mevatron MD2 (Siemens AG, USA, 1994) linear accelerator was used for the irradiation with 1 or 2 Gy. Treatment of the lymphocytes with cinnamic acid prior to irradiation reduced the number of micronuclei when compared with that in control samples. Treatment with cinnamic acid without irradiation did not increase the number of micronuclei and did not show a cytostatic effect in the lymphocytes. The results of the alkaline comet assay revealed that cinnamic acid reduces the DNA damage induced by X-rays, showing a significant radio-protective effect. Cinnamic acid decreased the frequency of irradiation-induced micronuclei by 16-55% and reduced DNA breakage by 17-50%, as determined by the alkaline comet assay. Cinnamic acid may thus act as a radio-protective compound, and future studies may focus on elucidating the mechanism by which cinnamic acid offers radioprotection.

Effects of Taxol plus radiation on the apoptotic and mitotic indices of mouse intestinal crypt cells

Purpose: In this study we investigated the effect of Taxol, radiation, or Taxol plus radiation on highly proliferative normal tissue – the intestinal crypt cells of Swiss albino mice. Materials and methods: Swiss-albino mice, 3–4 months old, were used in this study. Taxol was administered by bolus intravenously through the tail vein. Radiation was given using a linear accelerator. There were four treatment categories, which comprised a total of 34 groups. Each group consisted of five animals. The first category was a control category which comprised one group (n=5). The second treatment category was Taxol alone which comprised three groups (n=15). The third treatment category was radiation alone which comprised three groups (n=15). The fourth treatment category was Taxol plus radiation which comprised 27 groups (n=135). Mice were killed 24 h after Taxol or radiation or combined administration using ether anesthesia. Using a light microscope, apoptotic and mitotic indices were counted on jejunal crypt cells of mice that were stained with hematoxylin-eosin. Differences between groups were statistically evaluated with Students t-test. Results: Taxol caused a dose-dependent increase in apoptosis (P=0.045) and decreased the mitotic index (P=0.006) at high doses. Similarly, radiation caused a dose-dependent increase in apoptosis (P=0.046) and decreased the mitotic index (P=0.299) at higher radiation doses. Compared to radiation alone, Taxol caused a significant induction of apoptosis (P=0.010). In combination, no significant radiosensitizing effect of Taxol was observed (enhancement ratio <1), when compared to radiation alone. However, an increase in apoptosis was observed after 24 h of Taxol exposure when compared to 12 or 48 h of Taxol exposure (P=0.0001 and P=0.0001). Conclusion: These findings suggest that Taxol did not cause a radiosensitizing effect in intestinal crypt cells. However, a 24-hour pretreatment of Taxol exposure followed by radiation caused significant induction of apoptosis and reduction of the mitotic index when compared to other Taxol timing sequences. Thus, the lack of a radiosensitizing effect of Taxol in these proliferative cells may be due to enhanced mitotic death rather than apoptotic death.

Effects of EGFR, CK19, CK20 and Survinin gene expression on radiotherapy results in patients with locally advanced head and neck cancer.

PURPOSE To investigate the effects of epidermal growth factor receptor (EGFR), cytokeratin 19 (CK19), cytokeratin 20 (CK20) and survinin gene expression on local control (LC) and overall survival (OS) in patients with locally advanced head and neck cancer (LAHNC) who were administered radiotherapy (RT). MATERIALS AND METHODS Twenty-six patients who were admitted to Uludag University Medical Faculty Department of Radiation Oncology with a diagnosis of LAHNC (GIII-GIV) were included in this study. Gene expression was evaluated in tumor tissues and peripheral blood. RNA isolation was performed on paraffinized tumor tissues and peripheral blood samples obtained before RT (BR). The densities of the obtained RNAs were analyzed at 260/280 nm. cDNA samples obtained from total RNA,EGFR, CK19, CK20 and survinin gene expression levels were assessed via the Sybr Green method and data were analyzed with the ΔΔCt method. The same process was repeated for peripheral blood samples taken after RT (AR). RESULTS The female/male ratio was 3:23 and the mean age was 56.5 years (38-75 years). After radiotherapy, CK19 and CK20 levels in the peripheral blood were found to be correlated according to Pearson correlation analysis(p=0.049). This result indicates a possibility of remaining positive for CK19 and CK20 in the peripheral blood even after RT in patients with CK19, CK20, and EGFR positive tumors before RT. There was a statistically significant correlation between survinin levels measured BR and AR (p=0.028). CONCLUSIONS In this study, we found that patients with any EGFR, CK19, CK20 or survinin positivity in their peripheral blood obtain less benefit from radiotherapy. A wider patient population and advanced protein analyses are necessary in order to increase the reliability of our findings.

The evaluation of bcl-2 expression as a prognostic marker in early stage laryngeal cancer.

AIMS AND BACKGROUND To evaluate the effect of bcl-2 expression on the local control and overall survival of patients with early stage laryngeal cancer treated with radiotherapy alone. METHODS AND STUDY DESIGN We included 53 patients with stage Tis, T1, and T2 laryngeal cancer who were irradiated in our department. Paraffin blocks of all biopsy specimens were subjected to immunohistochemical analysis with a bcl-2 oncoprotein mouse clone 124 Scytek kit. RESULTS The mean follow-up time was 61 months (range, 7-166). Local-regional recurrence was observed in 10 (19%) patients. Forty-three patients (81%) had negative bcl-2 staining, 5 patients (9%) had + staining, 3 patients (6%) ++ staining, and 2 patients (4%) +++ staining. No relationship was detected between bcl-2 expression and local control or overall survival. The emergence of a recurrence and a younger age (<50 years) were significantly related to poor overall survival (P = 0.000 and P = 0.021, respectively). Patients with hemoglobin levels in the middle of radiotherapy and at the end of radiotherapy higher than 13 g/dl had improved overall survival in multivariate analyses (P = 0.002 and P = 0.001, respectively). Regarding local control, the following were poor prognostic factors: smoking more than 20 cigarettes a day (P = 0.001) and being younger than 50 years of age (P = 0.001). CONCLUSIONS No correlation was observed between bcl-2 expression and local control or overall survival. Whereas hemoglobin level, age and existence of a recurrence had a prognostic impact on overall survival, patient age and smoking status influenced local control rates.

Role of PET/CT in Treatment Planning for Head and Neck Cancer Patients Undergoing Definitive Radiotherapy

BACKGROUND In this study, we aimed to investigate the benefits of 18F-deoxyglucose positron emission tomography/computed tomography (FGD-PET/CT) imaging for staging and radiotherapy planning in patients with head and neck cancer undergoing definitive radiotherapy. MATERIALS AND METHODS Thirty-seven head and neck cancer patients who had undergone definitive radiotherapy and PET/CT at the Uludag University Medical Faculty Department of Radiation Oncology were investigated in order to determine the role of PET/CT in staging and radiotherapy planning. RESULTS The median age of this patient group of 32 males and 5 females was 57 years (13-84years). The stage remained the same in 18 cases, decreased in 5 cases and increased in 14 cases with PET/CT imaging. Total gross tumor volume (GTV) determined by CT (GTVCT-Total) was increased in 32 cases (86.5%) when compared to total GTV determined by PET/CT (GTVPET/CT-Total). The GTV of the primary tumor determined by PET/CT (GTVPET/CT) was larger in 3 cases and smaller in 34 cases compared to that determined by CT (GTVCT). The GTV of lymph nodes determined by PET/CT (GTVLNPET/CT) was larger in 20 cases (54%) and smaller in 12 cases (32.5%) when compared to GTV values determined by CT (GTVLNCT). No pathological lymph nodes were observed in the remaining five cases with both CT and PET/ CT. CONCLUSIONS We can conclude that PET/CT can significantly affect both pretreatment staging and assessed target tumor volume in patients with head and neck cancer. We therefore recommend examining such cases with PEC/CT before treatment.

Simulation and Patient Fixation Methods

Radiotherapy (RT) for breast cancer patients, the appropriate indications and use of modern methods has been confirmed positive contributions that disease, disease-specific and overall survival in meta-analysis [1, 2]. The aim of RT is homogeneous distribution of the dose required for tumor control (±5%) at the target volume while protecting healthy tissue [3]. RT techniques can be difficult and vary depending on the anatomic structure of the region to be irradiated (breast, chest wall, or regional lymphatic) that target volumes could be in different depths and geometries [3–5]. Over time, with technologic advances and increasing experience in clinical practice, different simulation and treatment techniques have been developed [6–17]. Beginning in the 1950s, use of megavoltage treatment equipment in modern RT processes has reached a new point, with the use of magnetic resonance imaging, positron emission tomography, and computed tomography (CT) for treatment planning and in determining the target volumes. In a realistic virtual environment, a large number of techniques can be reviewed and an optimal technique can be formed using modern planning computers. Intensity modulated radiotherapy is becoming increasingly popular for critical organ volumes and dose reductions better than for target volume can be achieved [18, 19].