The needle in the haystack: application of breast fine-needle aspirate samples to quantitative protein microarray technology

Cancer. 2007 Jun 25;111(3):173-84. doi: 10.1002/cncr.22686.


Background: There is an unmet clinical need for economic, minimally invasive procedures that use a limited number of cells for the molecular profiling of tumors in individual patients. Reverse-phase protein microarray (RPPM) technology has been applied successfully to the quantitative analysis of breast, ovarian, prostate, and colorectal cancers using frozen surgical specimens.

Methods: For this report, the authors investigated the novel use of RPPM technology for the analysis of both archival cytology aspirate smears and frozen fine-needle aspiration (FNA) samples. RPPMs were printed with 63 breast FNA samples that were obtained before, during, and after treatment from 21 patients who were enrolled in a Phase II trial of neoadjuvant capecitabine and docetaxel therapy for breast cancer.

Results: Based on an MCF7 cell line model of breast adenocarcinoma, the sensitivity of the RPPM detection method was in the femtomolar range with a coefficient of variance <13.5% for the most dilute sample. Assay linearity was noted from 1.0 microg/microL to 7.8 ng/microL total protein/array spot (R(2) = 0.9887) for a membrane receptor protein (epidermal growth factor receptor; R(2) = 0.9935).

Conclusions: The results from this study indicated that low-abundance analytes and phosphorylated and nonphosphorylated proteins in specimens that consist of a few thousand cells obtained through FNA can be quantified with RPPM technology. The ability to monitor the in vivo state of cell-signaling proteins before and after treatment potentially will augment the ability to design individualized therapy regimens through the mapping of aberrant cell-signaling phenotypes. The mapping of these protein pathways will further the development of rational drug targets.

Publication types

  • Research Support, N.I.H., Intramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bayes Theorem
  • Biopsy, Fine-Needle / methods
  • Breast / metabolism
  • Breast / pathology
  • Breast Neoplasms / metabolism*
  • Breast Neoplasms / pathology
  • Cell Line, Tumor
  • Cluster Analysis
  • Female
  • Humans
  • Microarray Analysis / methods*
  • Phosphoproteins / analysis
  • Protein Kinases / analysis
  • Proteome / analysis*
  • Proteomics / methods*
  • Reproducibility of Results


  • Phosphoproteins
  • Proteome
  • Protein Kinases