Antibody-drug conjugates (ADCs) combine the high specificity of monoclonal antibodies with the high anti-tumor activity of small molecular cytotoxic payloads. The anti-tumor activity of ADCs is mainly achieved by the direct blocking of the receptor by monoclonal antibodies, direct action and bystander effect of cytotoxic drugs, and antibody-dependent cell-mediated cytotoxicity and complement-dependent cytotoxicity. ADCs have been used in adjuvant therapy and rescue treatment of human epidermal receptor 2 (HER2)-positive breast cancer, greatly improving the prognosis of breast cancer patients. Several ongoing clinical trials of ADC for breast cancer and other solid tumors proved the potential of ADCs will provide more promising treatment options for patients with malignant tumors. This review introduces the mechanism and latest clinical progress of ADC drugs approved for HER2-positive breast cancer to guide clinical practice and conduct research.
Antineoplastic Agents/therapeutic use* ; Antineoplastic Agents, Immunological/therapeutic use* ; Breast Neoplasms/drug therapy* ; Female ; Humans ; Immunoconjugates/therapeutic use* ; Receptor, ErbB-2

Canonical Wnt/β-catenin signaling pathway is of great significance to the occurrence and progression of tumors which make it an exciting target in cancer therapy. The pathway is also required in regeneration of normal tissues, so the specificity of inhibitors targeting this pathway may be affected. The coactivator of β-catenin, B cell lymphoma 9 (BCL9), is highly expressed merely in tumor cells. Accordingly, inhibitors targeting the interaction between β-catenin and BCL9 may demonstrate robust specificity and minimal toxicity. BCL9 increases tumor growth, invasion and metastasis by promoting epithelial-mesenchymal transition, up-regulating vascular endothelial growth factor and CD44 expression and regulating cancer stem cell traits. BCL9 promises to be a new target for cancer therapy.

Objective:To explore the germline mutation frequency of genetic susceptibility genes and clinical characteristics in early-onset breast cancer (onset age ≤35 years) in China.Methods:Clinical information and peripheral blood of 150 patients aged 35 and younger diagnosed with breast cancer in Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College from January 1, 2015 to December 31, 2019 were collected. Then DNA was extracted to detect germline mutations in breast cancer susceptibility gene (BRCA) 1, BRCA2, ataxia telangiectasia mutated (ATM) , partner and localizer of BRCA2 (PALB2) , tumor protein 53 (TP53) and cell cycle checkpoint kinase 2 (CHEK2) genes. Mutations were interpreted as pathogenic, likely pathogenic, uncertain significance, likely benign and benign according to the classification criteria and guidelines for genetic variation. Patients were divided into mutation group ( n=18) and non-mutation group ( n=132) according to the presence or absence of pathogenic or probable pathogenic germline mutations, and the χ2 test was used to analyze the relationships between genetic susceptibility gene mutations and clinicopathological characteristics. Results:Eighteen pathogenic or likely pathogenic germline mutations were detected in 150 patients with early-onset breast cancer, for an overall mutation frequency of 12.0%. Among them, there were 8 (5.3%) BRCA2 mutation, 7 (4.7%) BRCA1 mutation, 1 (0.7%) PALB2 mutation, and 2 (1.3%) TP53 mutation. There were no pathogenic or likely pathogenic variants in ATM and CHEK2 genes. The mutation type was dominated by frameshift mutation (9/18, 50.0%) , followed by nonsense mutation (7/18, 38.9%) , missense mutation (1/18, 5.6%) and splice acceptor mutation (1/18, 5.6%) . Among the molecular subtypes of 18 mutation carriers, 9 cases were Luminal B, 6 cases were triple negative breast cancer (TNBC) , 2 cases were Luminal A, and only 1 case was human epidermal growth factor receptor-2 (HER-2) amplification. Among them, 8 BRCA2 mutation carriers were Luminal type, and 6 of 7 BRCA1 mutation carriers were TNBC type. There were no statistical differences in family history of breast cancer ( P=0.343) , estrogen receptor (ER) status ( χ2=0.16, P=0.688) , HER-2 status ( χ2=2.89, P=0.089) , molecular subtype ( χ2=1.99, P=0.575) , and initial diagnosis TNM stage ( χ2=2.49, P=0.115) between the mutation group and the non-mutation group. Conclusion:The patients with early-onset breast cancer have high frequency of germline mutations. It is recommended that patients with early-onset breast cancer undergo genetic counseling and multigene testing.

Objective:To explore the high risk factors of catheter-related thrombosis (CRT) in breast cancer patients, and provide the basis for the development of appropriate prevention and treatment strategies.Methods:A total of 1 432 breast cancer patients scheduled to receive central venous catheterization in National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College from January 1, 2015 to August 31, 2019 were selected. Baseline information and catheterization information of patients were collected. The occurrence of CRT was confirmed by vascular ultrasound examination, and the influencing factors of CRT were analyzed.Results:The total number of catheter days were 121, 980 days in 1 432 patients with breast cancer, and the average number of catheter days in each patient was 85.2 days. The incidence of CRT was 6.8% (97/1 432), which was 0.79 cases/1 000 catheter days. Among 815 patients with centrally inserted central venous catheters (CICC), 43 (5.3%) had CRT, which was 0.70 cases/1 000 catheter days. Among 617 patients with peripherally inserted central venous catheters (PICC), 54 (8.8%) developed CRT, which was 0.90 cases/1 000 catheter days. CRT was most common in subclavian vein (63.9%). Multivariate regression analysis showed that age ≥ 60 years old ( OR=1.712, 95% CI: 1.056-2.775, P=0.029), PICC ( OR=1.732, 95% CI: 1.130-2.656, P=0.012), the catheter position except subclavian vein ( OR=10.420, 95% CI: 1.207-89.991), secondary adjustment of catheter position ( OR=3.985, 95% CI: 1.510-10.521, P=0.005) and high D-Dimer level ( OR=1.129, 95% CI: 1.026-1.241, P=0.012)were independent risk factors for CRT. Conclusions:The CRT problem can′t be ignored in the clinical treatment of breast cancer patients with central venous catheterization. Screening the appropriate age of patients and the type of central venous catheters, reducing the secondary adjustment of catheter position, and timely monitoring the level of D-dimer are helpful to the prevention and treatment of CRT.

Objective:To explore the high risk factors of catheter-related thrombosis (CRT) in breast cancer patients, and provide the basis for the development of appropriate prevention and treatment strategies.Methods:A total of 1 432 breast cancer patients scheduled to receive central venous catheterization in National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College from January 1, 2015 to August 31, 2019 were selected. Baseline information and catheterization information of patients were collected. The occurrence of CRT was confirmed by vascular ultrasound examination, and the influencing factors of CRT were analyzed.Results:The total number of catheter days were 121, 980 days in 1 432 patients with breast cancer, and the average number of catheter days in each patient was 85.2 days. The incidence of CRT was 6.8% (97/1 432), which was 0.79 cases/1 000 catheter days. Among 815 patients with centrally inserted central venous catheters (CICC), 43 (5.3%) had CRT, which was 0.70 cases/1 000 catheter days. Among 617 patients with peripherally inserted central venous catheters (PICC), 54 (8.8%) developed CRT, which was 0.90 cases/1 000 catheter days. CRT was most common in subclavian vein (63.9%). Multivariate regression analysis showed that age ≥ 60 years old ( OR=1.712, 95% CI: 1.056-2.775, P=0.029), PICC ( OR=1.732, 95% CI: 1.130-2.656, P=0.012), the catheter position except subclavian vein ( OR=10.420, 95% CI: 1.207-89.991), secondary adjustment of catheter position ( OR=3.985, 95% CI: 1.510-10.521, P=0.005) and high D-Dimer level ( OR=1.129, 95% CI: 1.026-1.241, P=0.012)were independent risk factors for CRT. Conclusions:The CRT problem can′t be ignored in the clinical treatment of breast cancer patients with central venous catheterization. Screening the appropriate age of patients and the type of central venous catheters, reducing the secondary adjustment of catheter position, and timely monitoring the level of D-dimer are helpful to the prevention and treatment of CRT.

Immunogenic Cell Death ; Prognosis ; Immunotherapy ; Neoplasms