title: Differential expression of prognostic biomarkers between interval and screen-detected breast cancers: does age or family history matter?
abstract: The aim of this study was to compare tumor expression of prognostic biomarkers between interval breast cancers and screen-detected breast cancers overall, and according to age at diagnosis and familial risk. Tissue micro-arrays were constructed from 98 breast cancers (47 interval and 51 screen-detected) diagnosed in women in the Cancer Genetics Network. Arrays were immuno-stained to compare protein expression of six biomarkers including estrogen and progesterone receptor (ER/PR), Her2/neu, EGFR, cytokeratin 5/6, and Ki67. Fisher's Exact test was used to compare expression between interval and screen-detected cancers. Interval cancers were larger (P = 0.04), higher stage (P < 0.001), and more likely to have lobular histology (P = 0.01) than screen-detected cancers. Overall, interval cancers more often overexpressed EGFR (P = 0.01) and were somewhat more likely to be ER- (55% vs. 43%, P = 0.3), and triple negative (ER-/PR-/Her2-) (21 vs. 12%, P = 0.26). A greater difference in the proportion of interval versus screen-detected tumors that were ER- (53 vs. 35%; P = 0.29), PR- (35 vs. 21%; P = 0.25) and EGFR+ (17 vs. 0%; P = 0.02) was evident among women over 50. There was a trend toward differential expression among women with familial risk for PR- (P = 0.005) and triple negative status (P = 0.02). This study provides new data indicating that EGFR may be important in the etiology of interval cancer and be a possible therapeutic target. Our data also suggest that biological differences between interval and screen-detected cancers are more defined in older women. Future studies to confirm this finding and to elucidate novel markers for characterizing interval cancers may be more beneficial to this subgroup.
authors: Colorado School of Public Health, University of Colorado Denver, Aurora, CO 80045-0508, USA. jan.lowery@ucdenver.edu
authors: Jan T
authors: JT
authors: Lowery
authors: Tim
authors: T
authors: Byers
authors: John
authors: J
authors: Kittelson
authors: John E
authors: JE
authors: Hokanson
authors: Judy
authors: J
authors: Mouchawar
authors: John
authors: J
authors: Lewin
authors: Dan
authors: D
authors: Merrick
authors: Lisa
authors: L
authors: Hines
authors: Meenakshi
authors: M
authors: Singh
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000378:metabolism*; D001943:Breast Neoplasms / Q000175:diagnosis / Q000378:metabolism* / Q000473:pathology; D005260:Female; D006801:Humans; D008875:Middle Aged; D011379:Prognosis
chemical_list: D014408:Biomarkers, Tumor