6794

STK11

serine/threonine kinase 11;STK11;serine/threonine kinase 11

liver kinase B1|polarization-related protein LKB1|renal carcinoma antigen NY-REN-19|serine/threonine-protein kinase 11|serine/threonine-protein kinase LKB1|serine/threonine-protein kinase STK11

19p13.3

protein-coding

Germline mutations of the LKB1 tumor suppressor gene result in Peutz-Jeghers syndrome (PJS) characterized by intestinal hamartomas and increased incidence of epithelial cancers. Inactivating mutations in LKB1 have also been found in certain sporadic human cancers and with particularly high frequency in lung cancer. LKB1 has now been demonstrated to play a crucial role in pulmonary tumorigenesis, controlling initiation, differentiation, and metastasis. Recent evidences showed that LKB1 is a multitasking kinase, with great potential in orchestrating cell activity. Thus far, LKB1 has been found to play a role in cell polarity, energy metabolism, apoptosis, cell cycle arrest, and cell proliferation, all of which may require the tumor suppressor function of this kinase and/or its catalytic activity. This review focuses on remarkable recent findings concerning the molecular mechanism by which the LKB1 protein kinase operates as a tumor suppressor and discusses the rational treatment strategies to individuals suffering from PJS and other common disorders related to LKB1 signaling.

metastasis is characterized by the ability of cancer cells to invade into adjacent tissue, intravasate into blood or lymphatic vessels, and extravasate into a distant tissue. metastatic disease is primarily responsible for the low 5-year survival rate of non-small cell lung cancer (NSCLC), and therefore, an understanding of the molecular mechanisms that regulate NSCLC metastasis is clearly warranted. The serine/threonine kinase and tumor suppressor LKB1 is mutated in 30% of NSCLC tumors, and recent evidence points to a prominent role in NSCLC metastasis. This review summarizes LKB1-dependent invasion pathways where compromised LKB1 function could promote NSCLC metastasis.

BACKGROUND: Lymph node metastasis is the mayor cause of mortality in patients with head and neck squamous cell carcinomas (45%). The genetic changes underlying metastasis are still largely unknown and genetic markers to predict lymph node positivity still need to be found. The aim of this study was to search such markers by using Multiplex Ligation-dependent Probe Amplification (MLPA), a semi-quantitative PCR technique to detect gene copy number alterations. METHODS: Thirty-seven genes were analysed by MLPA in 34 larynx and 22 pharynx carcinomas. RESULTS: Losses of CDKN2A (9p21) and MLH1 (3p22) and gains of CCND1, EMS1 (both at 11q13), RECQL4 and PTP4A3 (both at 8q24) were the most frequent aberrations in both larynx and pharynx carcinomas. Amplifications were detected at EMS1, CCND1 and ERBB2 (17q21). A correlation between loss of N33 (8p22) and poor survival was found (p=0.02). Gain of EMS1 had the same relation with survival but not significant (p=0.08). Lymph node positive tumors presented a specific pattern of genetic alterations, with losses of N33, STK11 (19p13) and TP53 (17p13), the latter especially in larynx tumors. CONCLUSION: We propose that these 3 genes might play a role in the development of metastasis in larynx and pharynx squamous cell carcinomas.