Prognostic biomarkers in oral cancer : towards more individualized treatment

In patients with oral squamous cell carcinomas (OSCC), the presence or absence of regional lymph node metastases in the neck is the most striking determinant for both prognosis and treatment planning. Adequate determination of the nodal status in these patients is therefore crucial. Unfortunately, current diagnostic imaging modalities (i.e. magnetic resonance imaging, computed tomography and ultrasonography with fine-needle aspiration of suspicious nodes) lack sufficient sensitivity to detect small nodal metastases. As a result, a significant amount of about 30% of patients with small tumors unsuspected for lymph node metastasis, the so-called early OSCC (clinically T1-2N0), has occult nodal metastasis. Therefore, new diagnostic modalities are needed to improve the accuracy of determining the nodal status and pave the road for a more individualized treatment. In this thesis, molecular diagnostics on epigenetic, genetic and proteomic level were used to find prognostic biomarkers with could predict the presence or absence of these occult nodal metastasis in early OSCC. A well-known epigenetic event in carcinogenesis is promoter hypermethylation of tumor suppressor genes (TSG), which could lead to the inability to transcribe the gene and subsequent expressional suppression of the TSG. Although no correlation between promoter hypermethylation and nodal metastases was found, patients with early OSCC with two or more hypermethylated genes had an improved (disease specific) survival. Besides epigenetic events, series of well-defined structural genetic changes play a major role in the carcinogenesis of OSCC, for example DNA mutations and copy number aberrations in both oncogenes and TSGs. In a pilot study, 1.977 genes were sequenced to find somatic mutations or mutational altered pathways which could trigger the primary tumor to metastasize. This so-called “cancer mini-genome” includes all up today known oncogenes, tumor suppressor genes, all kinases and important pathways related to carcinogenesis and anti-cancer treatment. This gave a good insight in the mutational landscape of early OSCC. However, no correlation between the mutational landscape of the cancer mini-genome and nodal metastases was found. Copy number aberrations (CNA) of 36 genes were analyzed using in a consecutive cohort of 164 OSCC, including 144 clinically early OSCC, to investigate their value as prognostic biomarker for occult nodal metastasis. Gain of chromosomal region 11q13 (CTTN, FADD, CCND1 and FGF4) had the strongest correlation with occult LNM, with a negative predictive value of 81%. A literature review with meta-analysis confirmed the correlation between amplification of CCND1 and the presence of nodal metastasis in OSCC. However, evidence as biomarker for occult nodal metastasis in early OSCC was sparse. Therefore, the correlation of amplification of CCND1 as well as protein overexpression of its encoding protein Cyclin D1 was confirmed and validated in a multicenter study in early OSCC. This revealed Cyclin D1 overexpression as the best prognostic biomarker for occult lymph node metastasis in early floor of mouth OSCC

Prognostic biomarkers in oral cancer : towards more individualized treatment

In patients with oral squamous cell carcinomas (OSCC), the presence or absence of regional lymph node metastases in the neck is the most striking determinant for both prognosis and treatment planning. Adequate determination of the nodal status in these patients is therefore crucial. Unfortunately, current diagnostic imaging modalities (i.e. magnetic resonance imaging, computed tomography and ultrasonography with fine-needle aspiration of suspicious nodes) lack sufficient sensitivity to detect small nodal metastases. As a result, a significant amount of about 30% of patients with small tumors unsuspected for lymph node metastasis, the so-called early OSCC (clinically T1-2N0), has occult nodal metastasis. Therefore, new diagnostic modalities are needed to improve the accuracy of determining the nodal status and pave the road for a more individualized treatment. In this thesis, molecular diagnostics on epigenetic, genetic and proteomic level were used to find prognostic biomarkers with could predict the presence or absence of these occult nodal metastasis in early OSCC. A well-known epigenetic event in carcinogenesis is promoter hypermethylation of tumor suppressor genes (TSG), which could lead to the inability to transcribe the gene and subsequent expressional suppression of the TSG. Although no correlation between promoter hypermethylation and nodal metastases was found, patients with early OSCC with two or more hypermethylated genes had an improved (disease specific) survival. Besides epigenetic events, series of well-defined structural genetic changes play a major role in the carcinogenesis of OSCC, for example DNA mutations and copy number aberrations in both oncogenes and TSGs. In a pilot study, 1.977 genes were sequenced to find somatic mutations or mutational altered pathways which could trigger the primary tumor to metastasize. This so-called “cancer mini-genome” includes all up today known oncogenes, tumor suppressor genes, all kinases and important pathways related to carcinogenesis and anti-cancer treatment. This gave a good insight in the mutational landscape of early OSCC. However, no correlation between the mutational landscape of the cancer mini-genome and nodal metastases was found. Copy number aberrations (CNA) of 36 genes were analyzed using in a consecutive cohort of 164 OSCC, including 144 clinically early OSCC, to investigate their value as prognostic biomarker for occult nodal metastasis. Gain of chromosomal region 11q13 (CTTN, FADD, CCND1 and FGF4) had the strongest correlation with occult LNM, with a negative predictive value of 81%. A literature review with meta-analysis confirmed the correlation between amplification of CCND1 and the presence of nodal metastasis in OSCC. However, evidence as biomarker for occult nodal metastasis in early OSCC was sparse. Therefore, the correlation of amplification of CCND1 as well as protein overexpression of its encoding protein Cyclin D1 was confirmed and validated in a multicenter study in early OSCC. This revealed Cyclin D1 overexpression as the best prognostic biomarker for occult lymph node metastasis in early floor of mouth OSCC

The diagnostic value of 11q13 amplification and protein expression in the detection of nodal metastasis from oral squamous cell carcinoma: a systematic review and meta-analysis

Despite improvements in both diagnostic and therapeutic strategies, the prognosis of oral squamous cell carcinoma (OSCC) has not changed significantly over the last decades. Prognosis of OSCC particularly depends on the presence of nodal metastasis in the neck. Therefore, proper determination of the nodal status is pivotal for appropriate treatment. Unfortunately, current available imaging techniques (magnetic resonance imaging or ultrasound even with fine needle aspiration of suspected lymph nodes (LNs)) fail to detect occult nodal disease accurately. Clinicians in head and neck oncology urgently need new diagnostic tools to reliably determine the presence of nodal metastasis of the neck. Gain of the chromosomal region 11q13 is one of the most prominent genetic alterations in head and neck cancer and is associated with poor prognosis and metastasis. The aim of this systematic review and meta-analysis was to determine the diagnostic value of either 11q13 amplification or amplification/protein overexpression of individual genes located on 11q13 to detect nodal metastasis in OSCC. A search was conducted in Pubmed, EMBASE, and Cochrane, and 947 unique citations were retrieved. Two researchers independently screened all articles and only 18 were found to meet our inclusion criteria and were considered of sufficient quality for meta-analysis. Pooled results of those show that both amplification of CCND1 and protein overexpression of cyclin D1 significantly correlate with lymph node metastasis (LNM) in OSCC. In addition, amplification of CCND1 shows a negative predictive value of 80 % in the detection of LNM in early stage OSCCs which are clinically lymph node negative although this evidence is sparse and should be validated in a larger homogeneous cohort of T1-2 OSCC

Predictive factors for premature loss of Martin 2.7 mandibular reconstruction plates

Mandibular reconstruction with a plate, with or without a vascularised free (bone) flap, is commonly used to treat patients with a segmental mandibular defect. Common complications are loosening of the osteosynthesis screws, malposition, intraoral or extraoral exposure, or infection. To define prognostic factors for premature loss of such plates and improve future planning, we designed a retrospective study of all patients operated on between 2005 and 2011 for reconstruction of a mandibular segmental defect with a reconstruction plate with or without a free vascularised (bone) flap. Prognostic factors collected from medical records were the patient's age, sex, and American Society of Anesthesiologists (ASA) grade; treatment with radiotherapy; whether they had diabetes or smoked; the site of the mandibular defect; whether there was a dental occlusion; the number of screws used on each side, and the use of a free vascularised (bone) flap; and whether the diagnosis was of oral cancer, benign tumour, or trauma. One hundred patients were included, 79 with oral cancer, 19 with benign tumours, and 2 with trauma. In 20 patients the Martin 2.7 reconstruction plate failed. Diabetes and smoking were significant prognostic factors for premature loss of the reconstruction plate with a hazard ratio of 2.95 (95% CI 1.068-8.172), p value = 0.04, for diabetes, and 2.42 (95% CI 1.006-5.824), p value = 0.05, for smoking. Smokers and diabetic patients have a higher risk of failure after mandibular reconstruction with a 2.7 reconstruction plate. (C) 2014 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved

Absent and abundant MET immunoreactivity is associated with poor prognosis of patients with oral and oropharyngeal squamous cell carcinoma

Although the receptor tyrosine kinase (RTK) MET is widely expressed in head and neck squamous cell carcinoma (HNSCC), its prognostic value remains unclear. This might be due to the use of a variety of antibodies and scoring systems. Here, the reliability of five commercial C-terminal MET antibodies (D1C2, CVD13, SP44, C-12 and C-28) was evaluated before examining the prognostic value of MET immunoreactivity in HNSCC. Using cancer cell lines, it was shown that D1C2 and CVD13 specifically detect MET under reducing, native and formalin-fixed paraffin-embedded (FFPE) conditions. Immunohistochemical staining of routinely FFPE oral SCC with D1C2 and CVD13 demonstrated that D1C2 is most sensitive in the detection of membranous MET. Examination of membranous D1C2 immunoreactivity with 179 FFPE oral and oropharyngeal SCC - represented in a tissue microarray - illustrated that staining is either uniform (negative or positive) across tumors or differs between a tumor's center and periphery. Ultimately, statistical analysis revealed that D1C2 uniform staining is significantly associated with poor 5-year overall and disease free survival of patients lacking vasoinvasive growth (HR = 3.019, p < 0.001; HR = 2.559, p < 0.001). These findings might contribute to reliable stratification of patients eligible for treatment with biologicals directed against MET