Abstract P4-01-09: γ-glutamyl hydroxymethyl rhodamine green (gGlu-HMRG) is promising fluorescence probe for rapid diagnosis of breast cancer; - The feasibility study of real time imaging for breast cancer examination -

【Background and Aim】

To date, fluorescence imaging has been used gradually for real time diagnosis in various clinical situations. Evaluation of margin on surgical specimens is essential to decide whether additional resection should be performed for breast cancer surgery. In the same context, rapid assessment of biopsy specimen is crucial because when they do not contain any part of the lesions, re-examination should be need.

A fluorescence probe named γ-glutamyl hydroxymethyl rhodamine green (gGlu-HMRG) was rapidly activated by an enzyme, γ-glutamyltransferase (GGT). It was overexpressed in variety of cancers so promising for clinical use. The aim of this study is to examine the usefulness of the probe for breast cancer detection.

【Material and Methods】

We investigated the patients of breast cancer or benign disease who received examination consecutively from March 2015 to February 2016 in our hospital. The samples were obtained by core needle biopsy (CNB) or vacuum-assisted breast biopsy (VAB).We sprayed the probe on these samples immediately after examination and shoot images by CCD camera. To evaluate the fluorescence intensity along the time, we used a filtered CCD camera that could detect specifically gGlu-HMRG color (Discovery® INDEC Medical Systems Inc.). The images were automatically obtained every 30 seconds for 10 minutes after adding the probe on the specimens.

The average value of the image in each region of interest (ROI) was analyzed using image analysis program Image J (https://imagej.nih.gov/ij/).

We investigated the change of fluorescence intensity with the passage of time. We also compared the fluorescence intensity of malignant lesions with benign ones, and analyzed whether the fluorescence intensity could distinguish the malignant lesions from benign ones.

【Result】

We obtained 362 samples from96 tumors. Fifty-six tumors with 215 samples were benign, while 40 tumors with 147samples are malignant histologically.

The fluorescence was immediately observed after sprayed the probe. The intensity had been increasing in proportion to time. The malignant specimens were rapidly increasing; in contrast, the benign ones were slowly. For example, when it took 60 seconds after spraying the probe that the intensity increase up to some level in malignant specimens, while benign one took 240 seconds up to the same level on average.

Comparing the malignant lesions with benign ones after sprayed 120 seconds, the fluorescence intensity was higher in malignant specimens than benign ones (average fluorescence intensity; benign 0.9, malignant 2.3 p=0.0138). By ROC analysis whether the fluorescence intensity could distinguish the malignant lesions from benign, AUC, sensitivity and specificity was 0.63, 70% and 57%, respectively (cut off 0.2).

【Conclusion】

The probe was contributory to distinguish malignant and benign lesions and may be useful for the rapid diagnosis of CNB in practice. We are now trying to seek a more accurate probe to differentiate benign and malignant lesion as a next step.

Citation Format: Takamaru T, Akashi ST, Kuwayama T, Sawada T, Hirota Y, Urano Y, Nakamura S. γ-glutamyl hydroxymethyl rhodamine green (gGlu-HMRG) is promising fluorescence probe for rapid diagnosis of breast cancer; - The feasibility study of real time imaging for breast cancer examination - [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P4-01-09.