Gastrointestinal Cancer

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SU_3_2026 - 53BP1 Deletion Induced Treatment Resistance in Neoadjuvant Chemoradiotherapy Rectal Patients By Inhibiting Immune Function

Sunday, October 21
1:15 PM - 2:45 PM
Location: Innovation Hub, Exhibit Hall 3

53BP1 Deletion Induced Treatment Resistance in Neoadjuvant Chemoradiotherapy Rectal Patients By Inhibiting Immune Function
H. Ma, T. Zhang, A. Huang, Y. Xiao, J. Yao, M. Jin, and L. Fan; Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China

Purpose/Objective(s): The tumor microenvironment could influence radiation treatment outcomes according to previous reports. 53BP1 deficiency was found to play pivotal role in inducing lymphocyte mature. Our previous studies indicate that 53BP1 protein deletion leaded to radiation resistance. Our study is to explore the relationship among 53BP1 protein expression, immune status, and radiation sensitivity.

Materials/Methods: From January 2015 to December 2017, 55 rectal cancer patients of advanced stage who received neoadjuvant chemoradiotherapy in Wuhan Union hospital were enrolled. The expression of 53BP1 protein in tumor specimens was detected by immunohistochemistry. Immune score was assessed to indicate the immune status of patients. There are three immune score systems, which are based on the numeration combination of two lymphocyte populations (CD3/CD45RO, CD3/CD8 or CD8/CD45RO) both in the center (CT) and the invasive margin (IM) of tumors. We detected the expression of CD3, CD8 and CD45RO in tumor specimens and three kinds of immune score was calculated. The descending rate, anus preservation rate, TRG stages of 55 patients who received surgery were collected and analyzed. We explore the influence of 53BP1 expression in tumor immune microenvironment, and radiation sensitivity.

Results: We analyzed 53BP1 protein expression and immune score in 55 patients, the descending rate was assessed by image data and confirmed by surgical specimen. The results indicated that immune score of CD3/CD8 is the most reasonable immune score in neoadjuvant chemoradiotherapy, the patients of 53BP1 deletion had more percentage cases with lower expression of CD3, CD8 and CD45RO than the patients of 53BP1 high expression, leading to lower immune score (CD3+CD8≤2) (94.73% vs. 55.55%, P<0.005), and the descending rate in 53BP1 deletion group was significantly lower than that in 53BP1 high expression group (21.05% vs.63.88%, P<0.005).

Conclusion: 53BP1 deletion inhibited immunological infiltration in rectal cancer, subsequently inhibited the immune microenvironments which leads to treatment resistance in neoadjuvant chemoradiotherapy.

Author Disclosure: H. Ma: None. T. Zhang: None. Y. Xiao: None. J. Yao: None.

Hong Ma

Biography:
Radiologist and Oncologist, Attending doctor in Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China

Education
1. Medicine. Doctor., 2007/03 - 2008/09, the University of Saar University School of medicine, cancer radiation oncology laboratory, Tutor: Prof. Dr. Ch. Rübe;
2. Master degree, 2000/07 - 2003/07, Sun Yixian Hospital, Affiliated to Zhongshan Medical University, Tutor: Zhu Zhaohua

Working Experience
 Attending doctor, 2003/07-present, Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology;

Publications
1. Ma H#*, Bi J, Liu T, Ke Y, Zhang S, Zhang T*. Icotinib hydrochloride enhances the effect of radiotherapy by affecting DNA repair in colorectal cancer cells. Oncol Rep. 2015 Mar;33(3):1161-70
2. Ma H#, Han J#, Zhang T*, Ke Y. Comparison of dosiology between three dimensional conformal and intensity-modulated radiotherapies (5 and 7 fields) in gastric cancer post-surgery. J Huazhong Univ Sci Technolog Med Sci. 2013 Oct;33(5):759-64.
3. Yao J#, Huang A#, Zheng X, Liu T, Lin Z, Zhang S, Yang Q, Zhang T, Ma H*. 53BP1 loss induces chemoresistance of colorectal cancer cells to 5-fluorouracil by inhibiting the ATM-CHK2-P53 pathway. J Cancer Res Clin Oncol. 2017 Mar;143(3):419-431.
4. Zhang T#, Liang ZW#, Han J, Bi JP, Yang ZY, Ma H*. Double-arc volumetric modulated therapy improves dose distribution compared to static gantry IMRT and 3D conformal radiotherapy for adjuvant therapy of gastric cancer. Radiat Oncol. 2015 19;10(1):114.
5. Xiao, Y#., Zheng, X#., Huang, A., Liu, T., Zhang, T*., Ma, H*. Deficiency of 53BP1 inhibits the radiosensitivity of colorectal cancer. International Journal of Oncology. 2016 Oct; 49(4):1600-8.
6. Bi J#, Huang A#, Liu T, Zhang T, Ma H*. Expression of DNA damage checkpoint 53BP1 is correlated with prognosis, cell proliferation and apoptosis in colorectal cancer. Int J Clin Exp Pathol. 2015 Jun 1; 8(6):6070-82.

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