Vasiliki Malamou-Mitsi

The role of reactive oxygen species and oxidative stress in environmental carcinogenesis and biomarker development

Although we have greatly benefited from the use of traditional epidemiological approaches in linking environmental exposure to human disease, we are still lacking knowledge in to how such exposure participates in disease development. However, molecular epidemiological studies have provided us with evidence linking oxidative stress with the pathogenesis of human disease and in particular carcinogenesis. To this end, oxidative stress-based biomarkers have proved to be essential in revealing how oxidative stress may be mediating toxicity induced by many known carcinogenic environmental agents. Therefore, throughout this review article, we aim to address the current state of oxidative stress-based biomarker development with major emphasis pertaining to biomarkers of DNA, lipid and protein oxidation.

Human papillomavirus testing and the outcome of treatment for cervical intraepithelial neoplasia.

OBJECTIVE To investigate whether human papillomavirus (HPV) testing could be used in the follow‐up after large loop excision of the transformation zone (LLETZ) for cervical intraepithelial neoplasia (CIN). METHODS We performed a retrospective study of 41 women who developed subsequent CIN after LLETZ (group A) and 82 women without CIN for a minimum of 5 years after LLETZ (group B). The first post‐treatment cervical smear was retrieved and examined for high‐risk HPV deoxyribonucleic acid. The sensitivity, specificity, positive and negative likelihood ratio of HPV testing, first post‐treatment Papanicolaou test, and excision margins for the detection of treatment failure were calculated. Multiple logistic regression analysis was also done. RESULTS The HPV test was positive in 38 of 41 women in group A and 13 of 82 in group B (P < .001). An abnormal cytologic result in the first post‐treatment smear was found in 20 of 41 in group A and 11 of 82 in group B (P < .001). Sixteen women in group A and 18 in group B had involved margins (P = .046). Values for the sensitivity, specificity, and positive and negative likelihood ratios of the HPV test were 93%, 84%, 5.8, 0.08; for the Papanicolaou test they were 49%, 87%, 3.9, 0.586; and for margin status they were 39%, 78%, 1.8, 0.782, respectively. Positive HPV test presents significantly high odds ratio for treatment failure (P < .001), independent of cytology and margin status. CONCLUSION Women who postoperatively have positive HPV testing are at higher risk of treatment failure. This could be performed at the first post‐treatment visit and further follow‐up could be adjusted accordingly.

Angiogenesis in cancer of unknown primary: clinicopathological study of CD34, VEGF and TSP-1

BackgroundCancer of unknown primary remains a mallignancy of elusive biology and grim prognosis that lacks effective therapeutic options. We investigated angiogenesis in cancer of unknown primary to expand our knowledge on the biology of these tumors and identify potential therapeutic targets.MethodsParaffin embedded archival material from 81 patients diagnosed with CUP was used. Tumor histology was adenocarcinoma (77%), undifferentiated carcinoma (18%) and squamous cell carcinoma (5%). The tissue expression of CD34, VEGF and TSP-1 was assessed immunohistochemically by use of specific monoclonal antibodies and was analyzed against clinicopathological data.ResultsVEGF expression was detected in all cases and was strong in 83%. Stromal expression of TSP-1 was seen in 80% of cases and was strong in 20%. The expression of both proteins was not associated with any clinical or pathological parameters. Tumor MVD was higher in tumors classified as unfavorable compared to more favorable and was positively associated with VEGF and negatively with TSP-1.ConclusionAngiogenesis is very active and expression of VEGF is almost universal in cancers of unknown primary. These findings support the clinical investigation of VEGF targeted therapy in this clinical setting.

The role of epigenetics in environmental and occupational carcinogenesis

Over the last few years there has been an increasing effort in identifying environmental and occupational carcinogenic agents and linking them to the incidence of a variety of human cancers. The carcinogenic process itself is multistage and rather complex involving several different mechanisms by which various carcinogenic agents exert their effect. Amongst them are epigenetic mechanisms often involving silencing of tumor suppressor genes and/or activation of proto-oncogenes, respectively. These alterations in gene expression are considered critical during carcinogenesis and have been observed in many environmental- and occupational-induced human cancers. Some of the underlying mechanisms proposed to account for such differential gene expression include alterations in DNA methylation and/or histone modifications. Throughout this article, we aim to provide a current account of our understanding on how the epigenetic pathway is involved in contributing to an altered gene expression profile during human carcinogenesis that ultimately will allow us for better cancer diagnostics and therapeutic strategies.

High Incidence of Malignant Pleural Mesothelioma in Neighbouring Villages of Northwestern Greece

Between 1981 and 1985 seven patients from three villages of the Metsovo area in Northwestern Greece (population 5000) developed malignant pleural mesothelioma (MPM). The diagnosis was made with pleural biopsy and pleural fluid cytology. Six of these patients have died 18-24 months after the first symptoms (usually dyspnea on exertion) and 1 is still alive after 24 months. Seven MPMs in 5,000 in five years is about 280 times the expected incidence of 1/1,000,000/year. In the same area, endemic pleural calcifications linked to nonoccupational asbestos exposure have recently been reported, but none of our patients with MPM had pleural calcifications. The combination of MPM and pleural plaques in such a high frequency in the same area strongly suggests asbestos fiber as a common etiologic agent. On the other hand, the fact that the combination of MPM and pleural plaques did not occur in the same individuals, suggests a different response to this common offending agent.

High-risk human papillomavirus DNA test and p16INK4a in the triage of LSIL: A prospective diagnostic study

OBJECTIVE The detection of high-grade cervical intraepithelial neoplasia (CIN) amongst patients with low-grade cytology (LSIL) is challenging. This study evaluated the role of high-risk HPV (HR-HPV) DNA test and p16(INK4a) immunostaining in identifying women with LSIL cytology at risk of harboring CIN2 or worse (CIN2+) and the role of p16(INK4a) in the triage of a population of HR-HPV positive LSIL. METHODS We conducted a prospective study including women with LSIL cytology. Detection of HR-HPV was carried out by means of a polymerase chain reaction based assay. p16(INK4a) immunostaining was performed using the Dako CINtec cytology kit. All patients had colposcopically directed punch biopsies or large loop excision of the transformation zone of the cervix. The endpoint was detection of a biopsy-confirmed CIN2+. RESULTS A series of 126 women with LSIL cytology were included. HR-HPV test had sensitivity 75% and specificity 64% for an endpoint of CIN2+. p16(INK4a) had significantly higher specificity of 89% (p=0.0000) but low sensitivity of 42%. The role of p16(INK4a) immunostaining in the triage of LSIL positive for HR-HPV was also evaluated. p16(INK4a) triage had 70% positive predictive value (PPV); however, this was not significantly higher than the PPV (56%) of HR-HPV test alone (p=0.4). CONCLUSIONS The results indicate that HR-HPV or p16(INK4a) cannot be used as solitary markers for the assessment of LSIL. The addition of p16(INK4a) immunostaining led to an increase in HR-HPV specificity; however, the biomarker needs to be assessed further to establish its role as an adjunct test in the triage of LSIL.

Cervical regeneration after diathermy excision of cervical intraepithelial neoplasia as assessed by transvaginal sonography

OBJECTIVE To evaluate regeneration in cervical craters following large loop excision of the transformation zone (LLETZ) and to investigate possible differential healing patterns depending on the cones size. STUDY DESIGN A prospective study of 100 nulliparous women who underwent LLETZ. They underwent transvaginal scanning estimation of the cervical craters (diameter, depth) immediately post-operatively and at 3, 6 and 12 months. The crater dimensions of the women with the 25 largest cones were compared to those of the women with the 25 smallest cones in each of the above points of time. RESULTS The mean crater size of all women at 12 months was significantly smaller from the crater size immediately post-operatively. Although, there was a statistically significant difference in mean crater dimensions between the two quartile groups immediately post-operatively, no difference was found at 6 and 12 months. CONCLUSION There is a healing process of the cervical crater, which is almost completed by the sixth post-treatment month. The defect remaining in the cervix is similar whether a large or small excision was performed.

Transcription factor‐mediated proliferation and apoptosis in benign and malignant thyroid lesions

Transcription factors play an essential role in regulating both cell proliferation and programmed cell death. Proliferation and apoptosis‐related transcription factor immunoexpression patterns were concomitantly investigated in tissue sections of normal thyroid, goiters, follicular adenomas and well‐differentiated papillary and follicular carcinomas using antibodies against prothymosin α, E2F‐1, p53, Bcl2, and Bax proteins. Proliferation and apoptotic indices were determined by Ki‐67 immunoreactivity and the terminal deoxynucleotidyl transferase‐mediated deoxy uridine triphosphate nick‐end labeling technique, respectively. Prothymosin α and E2F‐1 immunoexpression levels were found to be significantly elevated in well‐differentiated carcinomas compared to adenomas, goiters and normal tissues (P < 0.05). Both proteins were directly correlated with the proliferation index (P < 0.05). E2F‐1 was additionally correlated with the apoptotic index (P < 0.05). The majority of cases were negative for p53 staining. Positive Bcl2 immunostaining was detected in all thyroid histotypes. None of the normal tissues showed Bax immunoreactivity, while positive accumulation differed significantly between hyperplastic and neoplastic histotypes. Direct correlations were observed between prothymosin α and Bcl2 as well as between E2F‐1 and Bax immunoexpression (P < 0.05). These data demonstrate that prothymosin α and E2F‐1 are strongly involved in the proliferation processes of thyroid neoplasias. Furthermore, prothymosin α may promote cell survival through the Bcl2 anti‐apoptotic pathway, while E2F‐1‐induced apoptosis via p53‐independent pathways may be associated with transcriptional activation of bax pro‐apoptotic gene.

Diffusion tensor and dynamic susceptibility contrast MRI in glioblastoma.

OBJECTIVE We prospectively investigated the correlation between diffusion tensor (DTI), dynamic susceptibility contrast (DSC) perfusion MRI metrics and Ki-67 labelling index in glioblastomas. METHODS We studied seventeen patients who were operated on for glioblastoma. DTI and DSC MRI were performed within a week prior to surgical excision. Lesion/normal ratios were calculated for the apparent diffusion coefficient (ADC), fractional anisotropy (FA), relative cerebral blood volume (rCBV), relative cerebral blood flow (rCBF) and relative mean transit time (rMTT) ratio. In the excised tumour specimens Ki-67 antigen expression was evaluated by the MIB-1 immunostaining method. RESULTS A significant correlation was observed between Ki-67 index and ADC ratio (r = -0.528, p = 0.029) and FA ratio (r = 0.589, p = 0.012). rCBV and rMTT presented a trend towards significant correlation with Ki-67 index (r = 0.628, p = 0.07 and r = 0.644, p = 0.06 respectively). There was a trend towards better survival for patients with gross total tumour excision and FA values lower than 0.48 (p = 0.1 and p = 0.09 respectively). No significant correlation was found between ADC ratio, rCBV, rCBF, rMTT and overall survival. CONCLUSION ADC ratio, FA ratio, rCBV and rMTT tumour/normal tissue ratios may represent indicators of glioma proliferation. FA values may hold promise for predicting survival in patients with glioblastoma.

Evaluation of the prognostic and predictive value of HER-1/EGFR in breast cancer patients participating in a randomized study with dose-dense sequential adjuvant chemotherapy.

Background: To assess the prognostic and predictive significance of HER-1/EGFR protein levels in high-risk patients with breast cancer treated with dose-dense sequential adjuvant chemotherapy. Methods: 595 high-risk breast cancer patients were treated with adjuvant anthracycline-based dose-dense sequential chemotherapy (E-CMF vs. E-T-CMF). Disease-free survival (DFS) was the primary end point. HER-1/EGFR was assessed by immunohistochemistry (IHC) in 312 patients. Results: HER-1/EGFR expression was detected in 54 of 312 patients (17%). Positive expression of HER-1/EGFR was significantly associated with negative receptor status (52 vs. 17%, p < 0.001), worse histological grade (70 vs. 45%, p = 0.001), HER-2 overexpression (46 vs. 27%, p = 0.01) and positive p53 expression (48 vs. 19%, p < 0.001). With a median follow-up of 7 years, the total number of relapses was 105 (34%), and the total number of deaths 69 (22%). The analysis for DFS provides significant evidence that the HER-1/EGFR effect on the risk of disease progression was different according to treatment (interaction p = 0.02). Regarding overall survival, a trend towards a significant difference for an interaction of HER-1/EGFR and treatment was found (p = 0.07). Conclusion: The present study demonstrated a differential effect of positive HER-1/EGFR expression in the two treatment groups, with HER-1/EGFR being a negative prognostic marker in the absence of paclitaxel.