Neoadjuvant systemic therapy for breast cancer patients means systemic treatments before operations.Combination chemotherapy,endocrine therapy and targeted therapy before operation can degrade the tumor staging and increase the breast-conserving rates.Neoadjuvant chemotherapy has been accepted as one of the standard therapies for patients with locally advanced breast cancers.In the neoadjuvant setting,the studies about the use of aromatase inhibitors and trastuzumab in selected patients have also made great progresses.

Objective To construct the KU80 inhibition cell model by RNAi in U2OS cell and to explore the relationship between the Ku80,telomeres and radiosensitivity in telomerase-negative tumor cells.Methods U2OS cells were transfected with the recombinant plasmids of pshRNA-K80 by the lipofectamine,and the stable transfected cell clones were selected by G418.After the selection,the cells were collected and analyzed by the flow cytometry.RT-PCR and Western blot were used to measure the expression of Ku80 and Real-time PCR was used to detect the length of telomeres.The radiosensitivity of U2OS was determined by clone formation array.Results The transfection efficiency of the positive cell clones detected by the flow cytometry was (83.23 ± 7.63) ％.The inhibition rate of the Ku80 gene transcription in the cell group with recombinant plasmid was(68.09 ± 1.16)％ and the inhibition rate of the Ku80 protein expression in the same group was (11.03 ± 2.45) ％.The results of Real-time PCR showed that the telomere length of the cell group with recombinant plasmid (1.07 ± 0.07) was significantly shorter than that of the control group (4.42 ± 1.30,F =38.58,P ＜ 0.05) and that of the empty plasmid group (4.11 ±0.84,F =38.58,P ＜ 0.05).Compared to the control group,the telomere length of the empty plasmid group did not changed(4.42 ±0.84 vs.4.11 ±0.84).U2OS cells with Ku80 expression suppressed had lower SF2 than that of the control cells (F =1089.61,P ＜0.05),and resulted in the SER of 1.47.Conclusions The Ku80 inhibition cell model in telomerase-negative U2OS cell line is successfully established which has the shorter telomere length,and is more sensitive to radiation.Telomere shortening caused by pshRNA-of Ku80 is likely to be one of the mechanisms of radiosensitization in this kind of cell model.

Objective To establish the mitochondrial DNA depleted cell line (ρ0 cells) of lung cancer cell A549 and to observe the radiosensitivity difference between ρ0 cells and normal A549 cells (ρ + cells).Methods The ρ0 cells were depleted of mitochondrial DNA by culturing chronically in the presence of low concentration of ethidium bromide (EB),and then the cell model was confined.Radiosensitivity of both ρ0 cells and ρ + cells was detected using the cologenic formation assay.After 6 MV X-ray irradiation in vitro,cell cycle distribution and reactive oxygen species (ROS) level were analyzed by flow cytometry and fluorescence microplate reader,respectively.Results A ρ0 cell line was successfully established and had a lower radiosensitivity than ρ + cells (t =12.57,P ＜ 0.01).After irradiation with a dose of 8 Gy,compared to ρ+ cells,ρ0 cells showed prolonged G2 arrest with less cells in G2 (t =6.82,P ＜ 0.01) and had lower increase of ROS level (t =14.51,P ＜ 0.01).Conclusions ρ0 cells have a lower radiosensitivity than ρ + cells,in which the reduction of ROS production and the prolongation of G2 arrest post-irradiation may be involved.

Objective: To investigate the relationship between systemic inflammatory markers such as neutrophil/lymphocyte ratio (NLR) and C-reactive protein/albumin ratio (CAR), and lymph node metastasis in patients with cN0 gastric cancer. To establish a nomogram model to predict the risk of lymph node metastasis in patients with cN0 gastric cancer. Methods: The preoperative systemic inflammatory markers and clinical data of 134 patients with cN0 gastric cancer were retrospectively analyzed, and these markers of patients with negative (pN0) or positive (pN+ ) lymph node metastasis in postoperative pathological diagnosis were compared. The receiver operating characteristic (ROC) curve was used to evaluate the predictive effect of preoperative systemic inflammatory markers on lymph node metastasis. The influencing factors for lymph node metastasis were assessed by univariate analysis and multivariate logistic regression analysis. A nomogram subsequently established by R software was validated by Bootstrap resampling as internal validation. Results: Compared with pN0 group, NE (P=0.022), CRP (P<0.001), NLR (P<0.001), PLR (P=0.003) and CAR (P<0.001) were higher, LY (P=0.003) and Alb (P=0.042) were lower in pN+ group. ROC curve analysis showed that the area under the curve (AUC) of postoperative pathological lymph node metastasis in patients with cN0 gastric cancer diagnosed by NLR, PLR and CAR were 0.687, 0.651 and 0.694, respectively, and the best cutoff values were 2.12, 113.59 and 0.02, respectively. The corresponding sensitivity and specificity were 62.9% and 72.2%, 77.4% and 48.6%, 74.2% and 58.3%, respectively. Univariate analysis showed that tumor size, depth of invasion, NLR, PLR and CAR were associated with lymph node metastasis in cN0 gastric cancer patients (all P<0.05). Multivariate analysis showed that depth of invasion, NLR and CAR were independent influencing factors of lymph node metastasis in patients with cN0 gastric cancer. OR were 8.084, 3.540 and 3.092, respectively (all P<0.05). The C-index of the nomogram model was 0.847 (95% CI: 0.782-0.915). The predicting calibration curve was properly fit with the ideal curve in calibration chart. Conclusion Combination of NLR and CAR to establish a nomogram model has a good consistency and can accurately predict the risk of lymph node metastasis in patients with cN0 gastric cancer.