Rabbit Anti-ERCC1 monoclonal antibody, clone KN21-18

A key step in the Fanconi anemia pathway of DNA interstrand crosslink (ICL) repair is the ICL unhooking by dual endonucleolytic incisions. SLX4/FANCP is a large scaffold protein that plays a central role in ICL unhooking. It contains multiple domains that interact with many proteins including three different endonucleases and also acts in several other DNA repair pathways. While it is known that its interaction with the endonuclease XPF-ERCC1 is required for its function in ICL repair, which other domains act in this process is unclear. Here, we used Xenopus egg extracts to determine ICL repair specific features of SLX4. We show that the SLX4-interacting endonuclease SLX1 is not required for ICL repair and demonstrate that all essential SLX4 domains are located at the N-terminal half of the protein. The MLR domain is crucial for the recruitment of XPF-ERCC1 but also has an unanticipated function in recruiting SLX4 to the site of damage. Although we find the BTB is not essential for ICL repair in our system, dimerization of SLX4 could be important. Our data provide new insights into the mechanism by which SLX4 acts in ICL repair.

OBJECTIVE: This study aims to investigate the significance of combined detection of HER2 gene amplification and chemosensitivity in gastric cancer. METHODS: Immunohistochemistry (IHC), fluorescence in situ hybridization (FISH) and fluorescence reverse-transcription polymerase chain reaction (RT-PCR) were used to analyze the expression of HER2 protein, HER2 gene amplification and the mRNA expression of ERCC1, TUBB3 and TYMS genes in 135 cases of gastric carcinoma. RESULTS: The expression rate of HER2 protein was 39.3% (53/135). Among these positive cases, patients with HER2 protein (3+) accounted for 9.6% (13/135), patients with HER2 protein (2+) accounted for 13.3% (18/135), and patients with HER2 protein (1+) accounted for 16.3% (22/135). The amplification rate of the HER2 gene was 35.8% (19/53). In the detection of the mRNA expression of ERCC1, TUBB3 and TYMS, 45 patients had low and moderate single gene expression, 50 patients had low and moderate double gene expression, 22 patients had low and moderate mRNA expression for ERCC1, TUBB3 and TYMS, and 18 patients had no low and moderate expression. Among the 53 patients with HER2 protein expression and 22 patients with low and moderate mRNA expression of ERCC1, TUBB3 and TYMS, 12 patients received chemotherapy and trastuzumab. Follow-up results revealed that HER2 gene status was positively correlated with the therapeutic effect of the combined treatment in patients with low mRNA expression of ERCC1, TUBB3 and TYMS. Among these patients, five patients with extensive HER2 (3+), HER2 cluster-specific amplification, and low mRNA expression of ERCC1, TUBB3 and TYMS had a total survival of up to 19.1 months. CONCLUSIONS: The detection of HER2 in gastric cancer is highly heterogeneity, and the combined detection of HER2 protein expression, HER2 gene amplification and chemosensitivity can provide important reference markers for the benefit of antitumor drugs.