Study on the protein expression and amplification of HER2 gene in gastric cancer

Objective: The aim of the study was to investigate the human epidermal growth factor receptor 2(HER2) gene amplification and protein expression and interpretation points in the stomach mixed carcinomas. Methods: Immunohistochemistry(IHC) and fluorescence in situ hybridization(FISH) technique were used to detect HER2 gene amplification and expression of HER2 protein in 442 cases of gastric mixed carcinoma. Results: The expression rate of HER2 protein was 41.2%(182/442): the HER2 protein expression IHC 3+ extensive type in 18 cases, partial type in 21 cases, focal type in 8 cases, accounting for 10.6%(47/442); the HER2 protein expression IHC 2+ extensive type in 23 cases, partial type in 28 cases, focal type in 11 cases, accounting for 14.0%(62/442); the HER2 protein expression IHC 1+ extensive type in 27 cases, partial type in 31 cases, focal type in 15 cases, accounting for 16.5%(73/442). HER2 gene amplification rate of 442 cases was 16.1%(71/442). In 182 cases of HER2 protein positive expression, the HER2 gene cluster amplification rate was 14.8%(27/182), large granular amplification rate 11.0%(20/182), punctate amplification rate 6.0%(11/182) and high polysomy 7.1%(13/182). In 71 cases of HER2 gene amplification, there was 42 cases of HER2 protein expression IHC 3+, 22 cases of HER2 protein expression IHC 2+, and 7 cases of IHC 1+. Conclusion: HER2 detection of gastric mixed carcinoma has great heterogeneity, HER2 protein positive expression is divided into extensive type, partial type and focal type, and HER2 gene positive amplification is divided into cluster amplification, large granular amplification, punctate amplification and high polysomy. These typing of HER2 protein expression and HER2 gene amplification provide reference index to quantify for targeted therapeutic effect of anticancer drugs.

In Vitro Nanobody Library Construction by Using Gene Designated-Region Pan-Editing Technology

Camelid single-domain antibody fragments(nanobodies)are an emerging force in therapeutic biopharmaceuticals and clinical diagnostic reagents in recent years.Nearly all nanobodies available to date have been obtained by animal immunization,a bottleneck restricting the large-scale application of nanobodies.In this study,we developed three kinds of gene designatedregion pan-editing(GDP)technologies to introduce multiple mutations in complementarity-determining regions(CDRs)of nanobodies in vitro.Including the integration of G-quadruplex fragments in CDRs,which induces the spontaneous multiple mutations in CDRs;however,these mutant sequences are highly similar,resulting in a lack of sequences diversity in the CDRs.We also used CDR-targeting traditional gRNA-guided base-editors,which effectively diversify the CDRs.And most importantly,we developed the self-assembling gRNAs,which are generated by reprogrammed tracrRNA hijacking of endogenous mRNAs as crRNAs.Using base-editors guided by self-assembling gRNAs,we can realize the iteratively diversify the CDRs.And we believe the last GDP technology is highly promising in immunization-free nanobody library construction,and the full development of this novel nanobody discovery platform can realize the synthetic evolution of nanobodies in vitro.