Patient-derived xenografts have been gold standards for cancer modeling and drug testing. However, low establishment efficiency and high maintenance cost have hindered the development in the field. Recently, patient-derived tumor organoid (PDO) cultures have been developed as an efficient and economic model to mimic and recapitulate the original tumor tissue. Due to the limited availability of current esophageal squamous cell carcinoma (ESCC) models, we aimed to establish PDO cultures for ESCC study. We have established and biobanked a panel of ESCC PDO cultures in vitro from Chinese ESCC treatment-naïve patients undergoing an endoscopic examination or upfront surgery, or patients undergoing neoadjuvant chemoradiotherapy (CRT) followed by surgery in Hong Kong. We also established and maintained a panel of PDO-derived xenograft (PDOX) in immunocompromised mice. Genomic profiling showed consistent mutational landscapes of the established PDOs, as compared to ESCC patient profiles. Transcriptomic profiling suggests PDOs closely resemble patient tumor samples. In vitro chemotherapy treatments followed by prolonged recovery suggests the existence of a subpopulation of persistent cells likely enriched by neoadjuvant CRT and well-preserved by organoid cultivation. Coupled with live-cell bioluminescent-based quantification techniques, PDO cultures can be employed in high-throughput therapeutic screening. Immunohistochemical examination confirmed the squamous origin of the PDOs and PDOXs. Slow-proliferating PDOXs allow adequate interaction between the cancer cells and the host and are useful as a suitable preclinical drug testing platform. ESCC PDOs can be efficiently established from highly limited patient tissue samples and maintained long-term in vitro and can be feasibly integrated with mouse models. ESCC PDOs and PDOXs serve as novel models for ESCC basic and translational studies.

Background Vocal cord paresis (VCP) is a serious complication after esophagectomy. Conventional diagnosis of VCP relies on flexible laryngoscopy (FL), which is invasive. Laryngeal ultrasonography (LUSG) is non-invasive and convenient. It has provided accurate VC evaluation after thyroidectomy but it is unclear if it is just as accurate following esophagectomy. This prospective study evaluated the feasibility and accuracy of LUSG in VC assessment on day-1 after esophagectomy. Methods Consecutive patients from a tertiary teaching hospital who underwent elective esophagectomy were prospectively recruited. All received pre-operative FL, and post-operative LUSG and FL on Day-1, each performed by a blinded, independent assessor. The primary outcomes were feasibility and accuracy of LUSG in the diagnosis of VCP on Day-1 post-esophagectomy. The accuracy of voice assessment (VA) was analyzed. Results Twenty-six patients were eligible for analysis. The median age was 70 years (66-73). Majority were male (84.6%). Twenty-five (96.2%) received three-phase esophagectomy. Twenty-four (96%) had same-stage anastomosis at the neck. Three (11.5%) developed temporary and one (3.8%) developed permanent unilateral VCP. Overall VC visualization rate by LUSG was 100%; sensitivity, specificity, positive predictive value, negative predictive value (NPV) and accuracy of LUSG were 75.0%, 100%, 100%, 98.0%, 98.1% respectively, and superior to VA. Combining LUSG with VA findings could pick up all VCPs i.e. improved sensitivity and NPV to 100%. Conclusion LUSG is a highly feasible, accurate and non-invasive method to evaluate VC function early after esophagectomy. Post-operative FL may be avoided in patients with both normal LUSG and voice.Matrix Man-Him Fung and Ian Yu-hong Wong share equal contribution as co-first authors to this paper.

Background: Esophageal squamous cell carcinoma (ESCC) is one of deadliest esophageal malignancies in Asia. Cancer cachexia is a multifactorial body wasting syndrome and is one of the major causes of death in late-stage patients (1). It is characterized by skeletal muscle loss and atrophy, adipose and body wasting, and metabolic dysregulations and stress (1). ESCC is one of the cancer types with the highest morbidity and mortality rates due to cancer cachexia (2). However, there are few effective and approved treatments targeting cancer cachexia. Currently, cancer cachexia animal models are highly limited with few cancer types available as a pre-clinical drug testing platform, with none related to esophageal carcinoma (3). Results: Here we have developed a panel of ESCC patient-derived organoid xenograft (PDOX) mouse model based on our latest patient-derived organoid cultures originating from Hong Kong patients. Our immunodeficient mouse-based PDOX model resembles different cachexic phenotypes that cell line-derived xenograft lacks, including body (skeletal muscle and adipose tissue) wasting and functional signs (e.g. lack of body movement, reduced muscle strength, and loss of appetite). The slow-proliferating characteristic of the ESCC PDOX allows development of a cachexic condition before humane endpoint. Furthermore, our full panel of PDOX lines allowed us to identify the full spectrum, differential cachexia severity across mice bearing different PDOXs, indicating a heterogenous nature. We have comprehensively characterized the cachexia phenotypes and performed proof-of-concept preclinical drug tests using established anti-cachexic drugs; treated PDOX-bearing mice have improved body condition and function compared to the control, which were further verified by histological examinations of tissue samples. Molecular analysis showed that several classic cachexia related gene expressions were down-regulated in isolated liver (Il1b) and inguinal adipose tissues (adipose triglyceride lipase). Conclusions: Our ESCC PDOX model potentially serves as a great pre-clinical cachexia-targeted drug testing platform, providing more treatment options for ESCC patients for better disease management. Acknowledgement: We acknowledge the Research Grants Council (TRS T12-701/17-R to MLL) and the Food and Health Bureau (HMRF 06171566 to VZY) of Hong Kong Special Administrative Region for funding supports. We acknowledge DSMZ for the KYSE cell lines. We acknowledge the HKUMed-CPOS for providing imaging facilities. References:1. Baracos VE, et al. Cancer-associated cachexia. Nat Rev Dis Primers 2018;4:171052. Tanaka Y, et al. Recent advancements in esophageal cancer treatment in Japan. Ann Gastroenterol Surg 2018;2:253-653. Ballaro R, Costelli P, Penna F. Animal models for cancer cachexia. Curr Opin Support Palliat Care 2016;10:281-7 Citation Format: Bryan Chee-chad Lung, Valen Zhuoyou Yu, Ian Yu-hong Wong, Claudia Lai-yin Wong, Desmond Kwan-kit Chan, Fion Siu-yin Chan, Betty Tsz-ting Law, Ka-on Lam, Dora Lai-wan Kwong, Anthony Wing-ip Lo, Simon Law, Maira Li Lung. Modelling cancer cachexia using a comprehensive panel of heterogeneous esophageal squamous cell carcinoma xenografts for therapeutic application [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 363.