Clinical Impact of C-myc Oncogenic Diversity on Solid and Lymphoid Malignancies

Onset and progression of malignant tumors is a multistep process including a variety of gross chromosomal and specific genes' deregulation. Among oncogenes that are frequently altered in solid and also in hematological malignancies, the C-myc (gene locus: 8q24.21) plays a pivotal role. C-myc is a proto-oncogene encoding for a nuclear phosphoprotein implicated in cell cycle progression, apoptosis and cellular differentiation and transformation. The purpose of the current molecular review was to explore the differences of C-myc oncogenic activity in solid and lymphoid malignancies that modify its clinical impact on them. A systematic review of the literature in the international database PubMed was carried out. The year 2010 was set as a prominent time limit for the publication date of articles in the majority of them, whereas specific references of great importance and historical value in the field of C-myc gene discovery and analysis were also included. The following keywords were used: C-myc, oncogene, signaling pathway, malignancies, carcinoma, lymphoma. A pool of 43 important articles were selected for the present study at the basis of combining molecular knowledge with new targeted therapeutic strategies. C-myc oncogene demonstrates two different mechanisms of deregulation: amplification, mutation and translocation patterns. These particular aspects of gene alteration are unique for solid and non-solid (hematological) malignancies, respectively. C-myc is characterized by diversity regarding its deregulation mechanisms in malignancies derived from different tissues. C-myc translocation is sporadically combined with amplification ("complicon" formation) or mutations creating exotic genetic signatures. This "bi-phasic" C-myc deregulation model in the corresponding malignant tumor categories clinically affects the corresponding patients, also modifying the targeted therapeutic strategies on them.