The eukaryotic translation initiation factor eIF3a is one of the core subunits of the translation initiation complex eIF3, responsible for ribosomal subunit joining and mRNA recruitment to the ribosome. It is known to play an important role in general translation initiation as well as in the specific translational regulation of various gene products, among which many influence tumour development, progression, and the therapeutically important pathways of DNA damage repair. Therefore, beyond its role in protein synthesis, eIF3a is emerging as regulator in tumour pathogenesis and therapy response and, therefore, a potential tumor marker. By means of a tissue microarray (TMA) for histopathological and statistical assessment, we here show eIF3a expression in 103 cases of squamous cell carcinoma of the oral cavity (OSCC), representing tissues from 103 independent patients. A subset of the study cohort was treated with platinum based therapy. Our results show that the 170？kDa protein is upregulated in OSCC and correlates with good overall survival. Overexpressing tumors respond better to platinum-based chemotherapy, suggesting eIF3a as a putative predictive as well as prognostic tumor marker in OSCC. 1. Introduction Head and neck squamous cell carcinomas (SCCs) range at place six of the most common cancers worldwide. They are responsible for approximately 650,000 newly diagnosed tumors and an annual rate of 350,000 deaths [1]. Cancers of the oral cavity are a large subgroup (48%) of head and neck tumors, where more than 90% are SCCs [2]. The major risk factors for oral cancer development are smoking or chewing tobacco as well as alcohol abuse. In Asian countries, betel nut and gutkha quid consumption is responsible for exceptional high cancer prevalence [2]. Even if being independent risk factors, alcohol and tobacco show synergistic effects in increasing the risk of cancer development when used together. This is partially due to the fact that the consumption of alcohol increases the permeability of the oral mucosa which enables an enhanced effect of carcinogenic nitrosamines and polycyclic hydrogen contained in tobacco. Other risk factors are insufficient oral hygiene, chronic pressure by dental prostheses, and chronic diseases, including infection with human papilloma virus [3–5]. First diagnosis of oral squamous cell carcinomas (OSCC) is frequently at late disease stage, with two thirds of patients baring a tumor of stage III or IV. These tumors, therefore, go along with severe morbidity and a long-term survival lower than 50%, despite advances in surgery
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