QS209 - Distinguishing Metastatic Lymph Nodes in an Orthotopic Rectal Cancer Mouse Model Using Color-coded Fluorescence Labeling with Humanized Anti-CEA Antibody

Monday, June 3, 2024

1:42 PM – 1:45 PM ET, USA

Location: Room 327

Quick Shot Presenter(s)

HK

HYE-JIN KIM, n/a

Associated professor
Kyungpook National University Chilgok Hospital
Daegu, Taegu-jikhalsi, Republic of Korea

All relevant financial disclosures have been managed and will be listed below.
This individual has no financial relationships with ineligible companies.

Senior Author(s)

MB

Michael Bouvet, n/a

Professor
University of California San Diego
San Diego, California, United States

Disclosure information not submitted.

Author(s)

KC

Kristin Cox, n/a

Surgical resident
University of California San Diego
San Diego, California, United States

Disclosure information not submitted.
SL

Shanglei Liu, n/a

Professor
University of California San Diego
San Diego, California, United States

Disclosure information not submitted.
SA

Siamak Amirfakhri, n/a

Dr.
University of California San Diego
San Diego, California, United States

Disclosure information not submitted.
GC

GYU-SEOG CHOI, n/a

Professor
Kyungpook National University Chilgok Hospital
DAEGU, Taegu-jikhalsi, Republic of Korea

Disclosure information not submitted.
AD

Aylin Din Parast Saleh, n/a

Student
University of California San Diego
San Diego, California, United States

Disclosure information not submitted.
TL

Thinzar Lwin, n/a

Professor
City of Hope National Medical Center
irvine, California, United States

Disclosure information not submitted.
PY

Paul Yazaki, n/a

Professor
City of Hope National Medical Center
irvine, California, United States

Disclosure information not submitted.
RH

Robert Hoffman, n/a

Professor
AntiCancer, Inc.
San Diego, California, United States

Disclosure information not submitted.

Purpose/Background: Lymph node (LN) status is one of the most important prognostic factors in patients with colorectal cancer. However, distinguishing metastatic LNs during operation has struggled with low accuracy. Herein, the present study investigated the effectiveness of tumor-specific antibodies to discriminate metastatic LNs in the orthotopic rectal cancer mouse model.

Methods/Interventions: A rectal cancer with para-aortic LN metastasis mouse model was established by injecting human HT-29 colorectal cancer cells into the rectal submucosa. Humanized anti-CEA antibody (M5A) was used to label the tumor-bearing LNs. M5A conjugated to the near-infrared dye IR800CW (M5A-IR800CW) was administered 48 hours before fluorescence imaging. The maximal tumor-background ratio (TmaxBR) was used to assess the effectiveness of the intra-molecular imaging. The Pearl Small Imaging System was used for these studies.

Results/Outcomes: M5A-IR800CW was administered to six orthotopic rectal cancer mice. A total of 28 LNs were harvested, comprising 16 para-aortic LNs and 12 inguinal LNs. Among them, nine LNs in the para-aortic region were confirmed as malignant pathologically. In 800nm fluorescence imaging, the median TmaxBR was significantly higher in metastatic LNs when compared to benign LNs [4.46 (range, 2.80-5.15) vs. 1.83 (1.01-3.00); p < 0.001]. Furthermore, when we categorized LNs by location, the disparity in median TmaxBR between metastatic and nearby para-aortic benign LNs was more pronounced [4.46 (range, 2.80-5.15) vs. 1.63 (1.20-1.87); p < 0.001].

Conclusion/Discussion: Tumor-specific fluorescence imaging effectively distinguishes benign from metastatic LNs in an orthotopic rectal cancer mouse model. This readily translatable technique holds the potential to enhance tailored lymphadenectomy, thereby improving outcomes for colorectal cancer patients.