Aberrant DNA methylation has shown promise as a biomarker for the early detection of cancer. To discover novel genes frequently methylated at an early stage in colorectal cancer (CRC), DNA microarray analysis coupled with enriched methylated DNA was performed in primary tumors and compared with adjacent nontumor tissues of 12 patients with CRC at stages I to IV. Stepwise filtering for candidate selection in microarray data analysis yielded a set of genes that are highly methylated across all CRC tumors and that can be used as a composite biomarker for CRC detection. Verification assay identified the SDC2 gene as a potential methylation biomarker for early CRC detection. In clinical validation in tissues from 139 CRC patients, a much higher level of aberrant SDC2 methylation was measured in most primary tumors (97.8%), compared with corresponding nontumor tissue of CRC patients, irrespective of clinical stage. Clinical validation of SDC2 methylation in serum DNA from CRC patients (n = 131) at stages I to IV and from healthy individuals (n = 125) by quantitative methylation-specific PCR demonstrated a high sensitivity of 87.0% (95% CI, 80.0% to 92.3%) in detecting cancers, with a specificity of 95.2% (95% CI, 89.8% to 98.2%). Importantly, sensitivity at stage I was 92.3%, indicating the potential of SDC2 methylation as a blood-based DNA test for early detection of CRC.

Disruption of the function of tumor suppressor proteins occasionally can be dependent on their subcellular localization. In about 40% of the breast cancer tissues, p53 is found in the cytoplasm as opposed to the nucleus, where it resides in normal breast cells. This means that the regulation of subcellular location of p53 is an important mechanism in controlling its function. The transport factors required for the nuclear export of p53 and the mechanisms of their nuclear export have been extensively characterized. However, little is known about the mechanism of nuclear import of p53. p53 contains putative nuclear localization signals (NLSs) which would interact with a nuclear transport factor, importin ␣. In this report we demonstrate that importin ␣ binds to NLSI in p53 and mediates the nuclear import of p53. Reverse transcriptase-polymerase chain reaction and sequencing analyses showed that a truncated importin ␣ deleted the region encoding the putative NLS-binding domain of p53, suggesting that it could not bind to NLSs of p53 proteins. Binding of importin ␣ to p53 was confirmed by using yeast two-hybrid assay. When expressed in CHO-K1 cells, the truncated importin ␣ predominantly localized to the cytoplasm. In truncated importin ␣ expressing cells, p53 preferentially localized to cytoplasmic sites as well. A significant increase in the p21 waf1/cip1 mRNA level and induction of apoptosis were also observed in importin ␣ overexpressing cells. These results strongly suggest that importin ␣ functions as a component of the NLS receptor for p53 and mediates nuclear import of p53.p53 is a tumor suppressor gene and various p53 gene mutations are found in over 50% of all human cancers (1). Although inactivation of tumor suppressor proteins is generally thought to originate in their genetic mutations, disruption of their function can occasionally be independent of such mutations. Moll et al. (2) have reported that about 37% out of 27 samples of breast cancer tissues showed cytoplasmic localization of wild-type p53, resulting in inhibition of normal p53 function (2). Nuclear exclusion of wild-type p53 has also been reported in neuroblastoma and colon carcinoma cells (3, 4). In another study, wild-type p53 was located in the cytoplasm of human cervical carcinoma cell lines with integrated human papillomavirus-18 or -16 (5). In colon carcinoma, cytoplasmic accumulation of p53 correlates with unfavorable prognosis (4). These data indicate that the regulation of p53 subcellular location is an important mechanism in controlling p53 function.In eukaryotic cells, the nucleus is separated from the cytoplasm by the nuclear envelope. This spatial segregation requires a nuclear transport system to correctly import or export nuclear components at the proper time. The prototype of the nuclear transport signal is the classical nuclear localization signal (NLS), 1 and nuclear import of proteins bearing an NLS is dependent on two cellular factors termed importin ␣ and importin ␤ (6 -11). The initial cytoplasmic event in NLS-dependent...

Objective: This study aimed to assess the effects of remote ischemic preconditioning (RIPC) on liver function in donors and recipients after living donor liver transplantation (LDLT). Background: Ischemia reperfusion injury (IRI) is known to be associated with graft dysfunction after liver transplantation. RIPC is used to lessen the harmful effects of IRI. Methods: A total of 148 donors were randomly assigned to RIPC (n = 75) and control (n = 73) groups. RIPC involves 3 cycles of 5-minute inflation of a blood pressure cuff to 200 mm Hg to the upper arm, followed by 5-minute reperfusion with cuff deflation. The primary aim was to assess postoperative liver function in donors and recipients and the incidence of early allograft dysfunction and graft failure in recipients. Results: RIPC was not associated with any differences in postoperative aspartate aminotransferase (AST) and alanine aminotransferase levels after living donor hepatectomy, and it did not decrease the incidence of delayed graft hepatic function (6.7% vs 0.0%, P = 0.074) in donors. AST level on postoperative day 1 [217.0 (158.0, 288.0) vs 259.5 (182.0, 340.0), P = 0.033] and maximal AST level within 7 postoperative days [244.0 (167.0, 334.0) vs 296.0 (206.0, 395.5), P = 0.029) were significantly lower in recipients who received a preconditioned graft. No differences were found in the incidence of early allograft dysfunction (4.1% vs 5.6%, P = 0.955) or graft failure (1.4% vs 5.6%, P = 0.346) among recipients. Conclusions: RIPC did not improve liver function in living donor hepatectomy. However, RIPC performed in liver donors may be beneficial for postoperative liver function in recipients after living donor liver transplantation.