DNA hypermethylation biomarkers to predict response to cisplatin treatment, radiotherapy or chemoradiation: the present state of art.

BACKGROUND: Concurrent platinum-based chemoradiation significantly improved survival of advanced stage cervical patients over radiotherapy alone. However, the 5-year overall survival is still only 66%. Presently, no biomarkers are available to select those cervical cancer patients that might benefit from concurrent platinum-based chemoradiation therapy. DNA methylation is a well-established contributor to the regulation of gene transcription, predominantly causing transcriptional silencing. Differences in promoter hypermethylation patterns and subsequent silencing, could contribute to the variety of responses observed in clinical practice. Several clinical trials on various malignancies reported a better response when Decitabine was administered prior to or in combination with standard therapy. This sensitization is thought to be due to re-expression of tumor suppressor genes. However, not all patients might benefit from demethylating agents, since re-expression of oncogenes could render patients more resistant. AIM: In this review, we summarized the present state of art regarding hypermethylated genes and their affected signaling pathways that are associated with outcome after cisplatin treatment, radiotherapy or chemoradiation. Since only few studies were reported in cervical cancer, other malignancies were reviewed as well. CONCLUSIONS: From the data presented in this review, we conclude that, in order to select patients that benefit most optimally from demethylating strategies, a comprehensive screening of a large panel of methylation markers, associated with both good as well as poor clinical outcome have to be investigated. Since such panels are not available at this moment, global methylation screening approaches are required to profile such methylated genes. Such methylated gene profiles might be very useful to optimize personalized treatment planning not only in cervical cancer but also in other malignancies.

The role of ATM and 53BP1 as predictive markers in cervical cancer.

Treatment of advanced-stage cervical cancers with (chemo)radiation causes cytotoxicity through induction of high levels of DNA damage. Tumour cells respond to DNA damage by activation of the 'DNA damage response' (DDR), which induces DNA repair and may counteract chemoradiation efficacy. Here, we investigated DDR components as potential therapeutic targets and verified the predictive and prognostic value of DDR activation in patients with cervical cancer treated with (chemo)radiation. In a panel of cervical cancer cell lines, inactivation of ataxia telangiectasia mutated (ATM) or its substrate p53-binding protein-1 (53BP1) clearly gave rise to cell cycle defects in response to irradiation. Concordantly, clonogenic survival analysis revealed that ATM inhibition, but not 53BP1 depletion, strongly radiosensitised cervical cancer cells. In contrast, ATM inhibition did not radiosensitise non-transformed epithelial cells or non-transformed BJ fibroblasts. Interestingly, high levels of active ATM prior to irradiation were related with increased radioresistance. To test whether active ATM in tumours prior to treatment also resulted in resistance to therapy, immunohistochemistry was performed on tumour material of patients with advanced-stage cervical cancer (n = 375) treated with (chemo)radiation. High levels of phosphorylated (p-)ATM [p = 0.006, hazard ratio (HR) = 1.817] were related to poor locoregional disease-free survival. Furthermore, high levels of p-ATM predicted shorter disease-specific survival (p = 0.038, HR = 1.418). The presence of phosphorylated 53BP1 was associated with p-ATM (p = 0.001, odds ratio = 2.206) but was not related to any clinicopathological features or survival. In conclusion, both our in vitro and patient-related findings indicate a protective role for ATM in response to (chemo)radiation in cervical cancer and point at ATM inhibition as a possible means to improve the efficacy of (chemo)radiation.

Prognostic cell biological markers in cervical cancer patients primarily treated with (chemo)radiation: a systematic review.

The aim of this study was to systematically review the prognostic and predictive significance of cell biological markers in cervical cancer patients primarily treated with (chemo)radiation. A PubMed, Embase, and Cochrane literature search was performed. Studies describing a relation between a cell biological marker and survival in ≥50 cervical cancer patients primarily treated with (chemo)radiation were selected. Study quality was assessed, and studies with a quality score of 4 or lower were excluded. Cell biological markers were clustered on biological function, and the prognostic and predictive significance of these markers was described. In total, 42 studies concerning 82 cell biological markers were included in this systematic review. In addition to cyclooxygenase-2 (COX-2) and serum squamous cell carcinoma antigen (SCC-ag) levels, markers associated with poor prognosis were involved in epidermal growth factor receptor (EGFR) signaling (EGFR and C-erbB-2) and in angiogenesis and hypoxia (carbonic anhydrase 9 and hypoxia-inducible factor-1α). Epidermal growth factor receptor and C-erbB-2 were also associated with poor response to (chemo)radiation. In conclusion, EGFR signaling is associated with poor prognosis and response to therapy in cervical cancer patients primarily treated with (chemo)radiation, whereas markers involved in angiogenesis and hypoxia, COX-2, and serum SCC-ag levels are associated with a poor prognosis. Therefore, targeting these pathways in combination with chemoradiation may improve survival in advanced-stage cervical cancer patients.

Construction of a triple modified p53 containing DNA vaccine to enhance processing and presentation of the p53 antigen.

More effective and less toxic treatments are urgently needed in the treatment of patients with cancer. The tumour suppressor protein p53 is a tumour-associated antigen that could serve that purpose when applied in an immunologic approval to cancer. It is mutated in approximately 50% of the tumours resulting in p53 overexpression, which can serve as target for therapy. To improve the immunisation results in patients with p53 overexpression tumours we constructed a DNA vaccine that could lead to improved processing and presentation of p53 peptides in the MHC-class I. We constructed a triple modified p53 fusion protein containing DNA vaccine by (1) addition of a xeno-antigen (mouse or rat p53 fragment), (2) potentiation of intra-cytoplasmatic accumulation of p53 by deleting the nuclear signalling part, (3) improving the processing to peptides of p53 by addition of ubiquitin. In-vitro experiments confirmed correct construction of the DNA vaccine. Preliminary testing in normal and HLA-A2 mice of this triple modified p53 containing DNA construct meant for human application showed a trend towards a superior immunogenicity.

Expression of epidermal growth factor receptor (EGFR) and activated EGFR predict poor response to (chemo)radiation and survival in cervical cancer.

PURPOSE: Activation of the epidermal growth factor receptor (EGFR) signaling pathway has been reported to induce resistance to (chemo)radiation in cancers, such as head and neck cancer, whereas EGFR-targeted agents in combination with (chemo)radiation seem to improve treatment efficacy. The aim of this study was to determine the relation between proteins involved in the EGFR pathway and response to (chemo)radiation and survival in a large, well-documented series of cervical cancer patients. EXPERIMENTAL DESIGN: Pretreatment tissue samples of 375 consecutive International Federation of Gynecologists and Obstetricians stage Ib to IVa cervical cancer patients treated with (chemo)radiation between January 1980 and December 2006 were collected. Clinicopathologic and follow-up data were prospectively obtained during standard treatment and follow-up. Protein expression of EGFR, phosphorylated EGFR (pEGFR), PTEN, phosphorylated AKT, and phosphorylated extracellular signal-regulated kinase (pERK) was assessed by immunohistochemistry on tissue microarrays. RESULTS: EGFR staining was present in 35.3%, pEGFR in 19.7%, PTEN in 34.1%, phosphorylated AKT in 4.1%, and pERK in 29.2% of tumors. pEGFR staining was related to PTEN (P = 0.001) and pERK staining (P = 0.004). EGFR staining was inversely related to PTEN (P = 0.011). In multivariate analysis, membranous staining of EGFR [hazard ratio (HR), 1.84; 95% confidence interval (95% CI), 1.20-2.82; P = 0.005] and cytoplasmic staining of pEGFR (HR, 1.71; 95% CI, 1.11-2.66; P = 0.016) were independent predictors of poor response to (chemo)radiation. Membranous EGFR staining also was an independent prognostic factor for poor disease-specific survival (HR, 1.54; 95% CI, 1.09-2.17; P = 0.014). CONCLUSIONS: EGFR and pEGFR immunostainings are frequently observed and independently associated with poor response to therapy and disease-specific survival in cervical cancer patients primarily treated by (chemo)radiation. Our data present the EGFR pathway as a promising therapeutic target in already ongoing clinical trials.