RESUMO
BACKGROUND: The aim of the study was to determine factors influencing hepatocellular carcinoma (HCC) recurrence in a cohort of patients who underwent liver transplantation (LT) at a large, tertiary-care medical center. METHODS: A total of 132 patients with the diagnosis of HCC at time of transplant were evaluated for HCC recurrence over a 7-year period. Nine patients were found to have HCC recur post-LT. RESULTS: No significant demographic values were found to indicate recurrence. Pre-LT factors potentially influencing HCC recurrence rates included number of days between HCC diagnosis and date of LT (P = 0.015), caudate lobe involvement (P = 0.019), increased use of radiation therapies pre-LT (P = 0.011), and total number of locoregional therapies (LRT) pre-LT (P < 0.001). Post-transplant outcomes demonstrated a significant difference in deep venous thrombosis (DVT) in the recurrent vs. non-recurrent groups (P = 0.035). CONCLUSIONS: The prevalence of HCC recurrence in this study was lower than the national average, yet difficulty still exists in predicting pre-LT factors which may influence HCC recurrence rates.
RESUMO
BACKGROUND: The Hippo pathway regulates organ size by inhibiting cell proliferation and promoting cell apoptosis upon its activation. The Yes Associated Protein 1 (YAP1) is a nuclear effector of the Hippo pathway that promotes cell growth as a transcription co-activator. In human cancer, the YAP1 gene was reported as amplified and over-expressed in several tumor types. METHODS: Immunohistochemical staining of YAP1 protein was used to assess the expression of YAP1 in pancreatic tumor tissues. siRNA oligonucleotides were used to knockdown the expression of YAP1 and their effects on pancreatic cancer cells were investigated using cell proliferation, apoptosis, and anchorage-independent growth assays. The Wilcoxon signed-rank, Pearson correlation coefficient, Kendall's Tau, Spearman's Rho, and an independent two-sample t (two-tailed) test were used to determine the statistical significance of the data. RESULTS: Immunohistochemistry studies in pancreatic tumor tissues revealed YAP1 staining intensities were moderate to strong in the nucleus and cytoplasm of the tumor cells, whereas the adjacent normal epithelial showed negative to weak staining. In cultured cells, YAP1 expression and localization was modulated by cell density. YAP1 total protein expression increased in the nuclear fractions in BxPC-3 and PANC-1, while it declined in HPDE6 as cell density increased. Additionally, treatment of pancreatic cancer cell lines, BxPC-3 and PANC-1, with YAP1-targeting siRNA oligonucleotides significantly reduced their proliferation in vitro. Furthermore, treatment with YAP1 siRNA oligonucleotides diminished the anchorage-independent growth on soft agar of pancreatic cancer cells, suggesting a role of YAP1 in pancreatic cancer tumorigenesis. CONCLUSIONS: YAP1 is overexpressed in pancreatic cancer tissues and potentially plays an important role in the clonogenicity and growth of pancreatic cancer cells.