Objective:To analyze the expression profile of miRNA-34c in cervical cancer tissue and identify its novel target gene. Methods:The expression levels of miRNA-34c were detected in 34 paired cervical cancer tissues and normal paraneoplastic tissues via quantitative reverse transcription polymerase chain reaction (qRT-PCR). Polo-like kinase 4 (PLK4) is a target gene of miRNA-34c pre-dicted in the miRNA Target Database. Luciferase vector containing the binding site of miRNA-34c to PLK4 3'UTR and miRNA-34c mimic or negative control were co-transfected into HEK293T cells, and luciferase expression was examined. The miRNA-34c mimic or negative control was transfected into SiHa cells, and the mRNA or protein expression of PLK4 was detected via qRT-PCR or Western blot, respectively. Results:MiRNA-34c expression was lower in cervical cancer tissues than in normal paraneoplastic tissues. The miR-NA-34c mimics significantly inhibited luciferase activation in the HEK293T cells (P<0.01) and significantly decreased the mRNA and protein expression levels of PLK4 in the SiHa cells (P<0.01). Conclusion:MiRNA-34c is significantly decreased in cervical cancer tis-sues. Moreover, miRNA-34c can significantly repress the mRNA and protein expression levels of PLK4 by directly targeting the 3'UTR.

Objective To investigate the effect and mechanism of melatonin on bioactivity of fibroblasts from human hypertrophic scar.Methods Fibroblasts from hypertrophic scar were cultured and incubated with melatonin,melatonin and Luzindole,and Luzindole,respectively,for 24 h,and the media as control.XTT/PMS assay was used to measure the proliferation of fibroblasts,ELISA assay to detect the TGF-β1 production of fibroblasts,and the expression of cell a-SMA,collagen Ⅰ,collagen Ⅲ mRNA were determined with real-time PCR method.Results Compared with the control,melatonin at the concentration of 10-5mmol/L,10-3mmol/L,and 1 mmol/L could inhibit the proliferation of fibroblasts in a does-dependent manner (P＜0.05); melatonin at the concentration of 10-3 mmol/L could significantly decrease the TGF-β1 production and expression of a-SMA mRNA and collagen Ⅰ mRNA in fibroblasts from human hypertrophic scar (P＜0.05) ; the effect of melatonin on fibroblast was significantly blocked by Luzindole (P＜0.05),but melatonin could not inhibit collagen Ⅲ mRNA expression (P＞0.05).Conclusions Melatonin can significantly regulate the biological activity of fibroblasts from human hypertrophic scar through a receptor pathway.

OBJECTIVETo study the correction of algorithm for Varian enhanced dynamic wedge(EDW) factors and compare the dose/monitor unit (MU) deviation measured at the central axis of EDW field with that obtained by manual calculation or using the treatment planning system.

METHODSEDW factors and dose were measured with Thimble ion chamber at 10 cm depth under the water for 6 MV and 10 MV photon on Varian linear accelerator. The corresponding calculations were done with the radiation treatment planning system. An analytic formula, namely the MU Fraction model, was used to calculate the EDW factor, which was corrected with a constant factor. The MU of conventional 2-D planning derived from manual calculating, treatment planning system, and actual measurements were compared.

RESULTSWith the measured results as the standard, the corrected manual calculation deviation of EDW factors was significantly reduced. For photon 6 MV, the maximum deviation reduced from 4.2% to 1.3% for 60° symmetry fields was, and from -4.7% to -1.8% for asymmetric fields. For photon 10 MV, the maximum deviation for all EDW fields was reduced from -3.0% to 1.1%. Comparison of the manual calculations with the measured results showed a MU deviation for symmetric fields within 2%, and more than 5% for some asymmetric fields. The deviation between the calculations of the treatment planning and the measured results was less than 1.5%.

CONCLUSIONConstant factor correction can effectively reduce the deviation of manual calculation. For MU calculation of EDW field in conventional 2-D dimensional treatment planning, the corrected results of symmetric fields meet clinical requirements. While the minimum distance between the field edge and the central axis was less than 4 cm in asymmetric fields, the corresponding special method, measurement or the treatment planning system should be used to calculate the dose/MU.

Objective:To evaluate the preliminary clinical efficacy and safety of stereotactic body radiation therapy (SBRT) in combination with targeted therapy for metastatic renal cell carcinoma (mRCC).Methods:Clinical data of 58 patients with mRCC who were treated with SBRT in combination with targeted therapy in Sun Yat-sen University Cancer Center from June 2013 to December 2018 were retrospectively analyzed. Among them, 79.3% patients were classified as intermediate or high risk according to International Metastatic Renal Cell Carcinoma Database Consortium Criteria. The median biologically equivalent dose (BED) was 147 Gy (67 to 238 Gy).Results:Overall, 32, 13, 7, 5 and 1 patients received SBRT for 1, 2, 3, 4 and 6 metastatic sites (105 lesions) and 71.4% of them were bone lesions. Targeted therapy was continued during SBRT. With a median follow-up of 9.4 months (range 2.7 to 40.1 months), 18 patients died. The 1-year local control rate was 97.4%. The 1-year progression-free survival was 50.3%. The 1-and 2-year overall survival was 72% and 53%. Approximately 85% patients experienced pain relief after SBRT. Patients who achieved complete or partial response after SBRT obtained better overall survival than those with stable disease or disease progression (1-year overall survival: 83% vs. 48%, P=0.021). In the whole cohort, 6 cases developed Grade Ⅲ adverse events, 4 of which were Grade Ⅲ myelosuppression, 1 case of Grade Ⅲ neuropathy and 1 case of radiation-induced skin injury. Conclusion:Preliminary study reveals that combined use of targeted therapy and SBRT is an efficacious and safe treatment of advanced mRCC.

Objective:To provide evidence for the selection of fixation devices and CTV to PTV margins (M ptv) in precision radiotherapy for pelvic tumors by analyzing three fixation devices in precision radiotherapy for prostate cancer. Methods:From April 2015 to December 2020, 133 prostate cancer patients treated with pelvic drainage area irradiation in our center were retrospectively analyzed. The patients were fixed with 1.2m vacuum bag (n=39), 1.8m vacuum bag (n=44) and personalized prone plate by our center (n=50). Each patient was asked to complete our bowel and bladder preparation process before positioning and radiotherapy. The registration of CBCT to planned CT before each treatment adopted the same registration box and algorithm. Setup errors in the SI, LR and AP directions under qualified bowel and bladder conditions were recorded. Setup errors in three directions under three fixation devices and corresponding M ptv values were analyzed. The correlation between setup errors with age and body mass index (BMI) was analyzed. Results:Analysis of 3333 setup errors data showed: in the SI and LR directions, the mean setup errors of 1.2m vacuum bag (3.26mm, 2.34mm) were greater than those of 1.8m vacuum bag (2.51mm, P<0.001; 1.90mm, P<0.001), and personalized prone plate (3.07mm, P=0.066; 2.10 mm, P=0.009). In the AP direction, the mean setup errors of 1.2m vacuum bag (supine)(2.20mm) were smaller than those of 1.8m vacuum bag (3.33mm, P<0.001) and personalized prone plate (3.61mm, P<0.001). The setup errors of 1.8m vacuum bag in all directions were smaller than those of personalized prone plate (P≤0.028). According to Van Herk's expansion formula, the M ptv of 1.2m vacuum bag in three directions was approximately 4 mm. The M ptv of 1.8m vacuum bag and personalized prone plate in the SI and LR directions was approximately 3 mm, and more than 5 mm in the AP direction. The setup errors were not correlated with age or BMI. Conclusions:From the setup errors results of three devices, 1.8m vacuum bag is the best, followed by personalized prone plate. And supine position is better than prone position in the AP direction.

Objective:The aim of the study is to investigate the inter-observer and intra-observer precision in manually segmentation of organs-at-risk(OARs) for cervical cancer on the basis of MR image, and to preliminarily explore sequence selection designed for radiotherapy planning.Methods:Thirty cervical cancer patients scanned by MR-sim from 2016 to 2018 in the department of radiotherapy of Sun Yat-sen university cancer center were retrospectively analyzed. T1WI, T1dixonc and T2WI sequence from MR-simulator were selected and imported into Monaco planning system. Manual segmentation of 5 organs-at-risk (bladder, rectum, anal canal, and left/ right femoral head) was done by 2 independent experienced physicians on three sequences acquired from these patients. A month later, the second segmentation of the OARs in the T1WI sequence was done by one of the two physicians. Dice similarity coefficient (DSC), Hausdorff distance (HD) and position difference(Δ x, Δ y, Δ z) of each OAR were used to analyze the robustness of inter-observer and intra-observer segmentation OARs. Results:The HD values of five OARs segmentation by the two physicians in T1WI, T1dixonc and T2WI sequences and the same physician in T1WI at different time were all less than 2 mm; the position differences were less than 5 mm. The DSC values, HD values and difference position values of the two physician and the same physician at different time was positively correlated with the volume of OARs ( R=0.178-0.582, P<0.05). Due to the small volume of the anal canal (7.385±1.555) cm 3, the DSC values were less than 0.7 and the performance was slightly worse. The average DSC values of other OARs were all greater than 0.82. Comparing the DSC, HD and position differences of OARs in the three sequences, DSC values of rectum, left / right femoral head and bladder, HD values of left/right femoral head and rectum, and Δ z axis difference of anal canal and right femoral head of T1WI sequence were better than T1dixonc ( t=-3.116-3.604, P<0.05); DSC value of rectum and HD value of anal canal in T1WI sequence were better than T2WI sequence( t= 2.934, 3.677, P<0.05 ); T1dixonc sequence rectal DSC, right femoral head Δ z axis difference were slightly better than T2WI( t=6.806, 2.130, P<0.05 ). T2WI sequence bone tissue (left/right femoral head) stability was better than T1WI, T1dixonc, and the difference was statistically significant ( t=-6.580-6.542, P<0.05). Conclusions:From three index of DSC, HD and position difference, the robustness of inter-observer and intra-observer segmentation of bladder, rectum and femoral head are fine based on MR sequence, followed by anal canal. In addition, the robustness of OARs segmentation by T1WI sequence is better than that of T1dixonc and T2WI sequence.