Predicting Schwannoma Growth in a Tumor Model Using Targeted Imaging.

Area of Science:

• Neuro-oncology
• Medical imaging
• Immunotherapy

Background:

• Vestibular schwannoma (VS) is a common neurotology diagnosis often managed with observation.
• Predicting VS growth is challenging, hindering optimal "wait and scan" strategies.
• Previous radiographic indicators for VS growth prediction have been unsuccessful.

Purpose of the Study:

• To evaluate fluorescent imaging with immunotargets for predicting vestibular schwannoma growth rate.
• To assess the potential of VEGFR2 and Her2/Neu as immunotargets for VS growth prediction.

Main Methods:

• A murine subcutaneous tumor model using a rat-derived schwannoma cell line (R3) was established.
• Monoclonal antibodies targeting VEGFR2 and Her2/Neu were conjugated to a near-infrared probe (IRDye800).
• Mice received tail vein injections of targeted probes or isotype control, followed by serial near-infrared imaging and correlation with tumor size and growth rate.

Main Results:

• Strong correlations were observed between day 1 tumor fluorescence and maximum tumor volume in both anti-VEGFR2 (r²=0.92) and anti-Her2/Neu (r²=0.86) groups.
• Significant correlations were also found between maximum day 1 tumor signal and maximum tumor volume for both targeted antibodies.
• No such correlations were found in the control group, indicating the specificity of the targeted probes.

Conclusions:

• Both VEGFR2 and Her2/Neu show promise as immunotargets for predicting vestibular schwannoma growth.
• Near-infrared fluorescent imaging with these targets can effectively correlate with tumor size and growth rate in a preclinical model.
• This imaging approach may aid in refining observation strategies for patients with vestibular schwannoma.