iTRAQ proteomics of sentinel lymph nodes for identification of extracellular matrix proteins to flag metastasis in early breast cancer.

Patients with early breast cancer are affected by metastasis to axillary lymph nodes. Metastasis to these nodes is crucial for staging and quality of surgery. Sentinel Lymph Node Biopsy that is currently used to assess lymph node metastasis is not effective. This necessitates identification of biomarkers that can flag metastasis. Early stage breast cancer patients were recruited. Surgical resection of breast was followed by identification of sentinel lymph nodes. Fresh frozen section biopsy was used to assign metastatic and non-metastatic sentinel lymph nodes. Discovery phase included iTRAQ proteomics coupled with mass spectrometric analysis to identify differentially expressed proteins. Data is available via ProteomeXchange with identifier PXD027668. Validation was done by bioinformatic analysis and ELISA. There were 2398 unique protein groups and 109 differentially expressed proteins comparing metastatic and non-metastatic lymph nodes. Forty nine proteins were up-regulated, and sixty proteins that were down regulated in metastatic group. Bioinformatic analysis showed ECM-receptor interaction pathways to be implicated in lymph node metastasis. ELISA confirmed up-regulation of ECM proteins in metastatic lymph nodes. ECM proteins have requisite parameters to be developed as a diagnostic tool to assess status of sentinel lymph nodes to guide surgical intervention in early breast cancer.

Sentinel Node Mapping in Early Breast Cancer: A Randomized Comparison of Fluorescein Guided All India Institute of Medical Sciences, Anurag's Technique with Technetium-99 m Sulfur Colloid Plus Methylene Blue.

Purpose: Evaluation of fluorescein along with blue dye as an affordable tracer for sentinel node biopsy in comparison with technetium + methylene blue. A randomized trial was conducted with the following objectives: (1) to demonstrate that the identification of sentinel lymph node by fluorescein + methylene blue is not inferior to the identification by Tc-99 m sulfur colloid + methylene blue and (2) to evaluate the cost-effectiveness of sentinel node biopsy by above two tracers. Subjects and Methods: One-thirty patients above age 18 years presenting with early breast cancer T1, T2, N0 breast carcinoma were randomized to undergo sentinel node biopsy by either fluorescein + methylene blue or Tc-99 m sulfur colloid + methylene blue. Results: The sentinel lymph nodes were identified in 89% in Fluorescein + methylene blue group and 90.9% with Tc-99 m sulfur colloid + methylene blue group. The trial demonstrated noninferiority of fluorescein + methylene blue as compared to isotope + methylene blue with effect size = 1; 95% confidence interval- 9.54 to + 11.54. The fluorescein + methylene blue was more cost-effective than isotope guided sentinel node biopsy. Conclusion: Fluorescein-guided sentinel node biopsy is noninferior and more cost-effective than isotope-guided sentinel node biopsy.