The role of P53 in nasal-type extranodal NK/T-cell lymphomas in Hong Kong patients

Abstract

Extranodal NK/T-cell lymphomas (ENKTCL) are the cancers originated from natural killer cells (NK cells) or T cells. ENKTCL are subdivided into two groups, the nasal-type (NTNKTCL) and the extranasal-type (ENTNKTCL), with the former one being the more common subtypes. NTNKTCL are known for their high aggressiveness and poor prognosis. Currently there is no ideal treatment for NTNKTCL. P53 is a tumor suppressor gene, which prevents cancer development by induction of cell cycle arrest and apoptosis. Deregulation of P53, including P53 overexpression and P53 mutations, has been frequently reported in NTNKTCL. However, none of the studies has been carried out in Hong Kong, which has a high incidence of NTNKTCL. The current study is the first one to investigate the pathogenic role of P53 in NTNKTCL in Hong Kong patients. Deregulation of P53 was identified in Hong Kong NTNKTCL patients as reflected by a P53 overexpression rate of 42%. Additionally, linked P53 polymorphisms in intron 7, which comprise a C→T change at nucleotide 14181 and a T→G change at nucleotide 14201, were detected in three NTNKTCL patients. It was speculated that the observed P53 polymorphisms are a predisposition factor of NTNKTCL. Lastly, P53 overexpression was found to be significantly associated with elevated serum lactate dehydrogenase (LDH) level, and was suggestive of decreased patient survival though not at significant level in NTNKTCL patients, indicating a potential value of P53 overexpression as prognostic marker in NTNKTCL.