2008 Summer Meeting - Leeds - The Pathological Society of Great ...

P21Audit of HER2 Status of Core Biopsies and Excisions ofInvasive Breast CancerMToy 1 , AM Hanby 1 ,GCoast 1 , AM Shaaban 11 Department of Histopathology and Molecular Pathology, Leeds TeachingHospitals NHS TrustHER2 assays are routinely performed on both core biopsy and excisionspecimens in each breast cancer case. Debate exists as to the reliability andprecise clinical role of core biopsy assay.In order to establish the degree of concordance, an audit of all breast corebiopsy HER2 assays on confirmed breast cancer cases between January 2005and February 2008 was performed. Cases were identified by searching thepathology database for all patients with a core HER2 result and identifying anycorresponding excision testing. Discordant cases were reviewed in detail.Of 185 cases, 80 went on to have a HER2 assay on excision samples. Ofthese, six assays were discordant between core and excision. Four cases hadpositive cores with negative excision HER2 status, and two had negative coreswith positive excision results. All of the discordant cases had borderlineimmunohistochemistry scores on the core specimens and proceeded to FISHdetection of HER2 gene amplification. No heterogeneity in HER2 expressionwas identified on review of the excision samples.It is suggested that better fixation of core biopsies compared to someexcision specimens, perhaps together with neo-adjuvant chemotherapy, willaccount for most core-positive discordant results. As in other areas ofpathology, transcription errors may exist in some reports. However, this seriesindicates that it is generally safe to rely on core HER2 results without need for aroutine excision specimen assay, in the context of ongoing audit of these tests.P23Duct Diversity in the Human NippleMCurrie 1 , J Going 11 University of GlasgowBackground: To explain the small number of nipple ducts (< 10) which can becannulated in human breast, compared with a median of 27 ducts in the nippleduct bundle, Going and Moffat [J Pathol 2004] proposed that a few 'type A'ducts open on the nipple surface while more smaller-calibre 'type B' ductsoriginate from skin appendages. Subsequently, Rusby [Breast Cancer Res Treat2007] proposed that many ducts share a few common openings on the nipplesurface.Aims and methods: To explore these competing explanations by examiningduct immunophenotypes in the nipple duct bundle and duct morphology in theapex of the papilla. Coronal sections through the duct bundle at the nipple basein 10 mastectomies were stained with haematoxylin/eosin and immunostainedfor oestrogen and progesterone receptor; proliferation markers Ki-67 and mcm-3; E-cadherin; basal markers p63, CD10 and smooth muscle actin; basalcytokeratins 5, 14 and 17; luminal keratins 7/8 and 19; and Cox 2. Saggitalsections stained for haematoxylin/eosin, ck 7/8, ck 14 and PR were examinedfor 30 more cases.Results: There was no size or immunophenotype dichotomy of ducts in themain duct bundle. Some 'type A' ducts communicated directly via a 'waist'(diameter ~50µ) with an infundibulum opening onto the nipple surface, whileother ducts tapered to a pinpoint lumen (3 (ER and PgR), Herceptest score = 3+ (HER2) and anycells positive (EGFR or CK5/6). Basal status was determined by negativity forER and HER2 with positivity for EGFR and/or CK5./6. Data regarding age,invasive tumour size, lymph node status, DCIS grade, invasive grade andpresence of lymphovascular invasion were obtained from the database search.Sixty-six cases were analysed. Differences in percentages between DCIS andinvasive components were: ER=1.51%, PgR=6.06%, HER2 = 0%,EGFR=3.03% and CK5/6=0%. There was no significant difference betweenDCIS and invasive tumours for basal-like status in this cohort (p=0.48). Nosignificant difference was observed for age, tumour size, lymph node status,DCIS grade, invasive grade or presence of lymphovascular invasion afteradjustment for multiple analyses in this small cohort. We conclude there isevidence of a DCIS precursor to invasive basal-like cancer, within a triplenegative cohort.P24CD109 expression in basal-like breast carcinomaM Hasegawa 1 , S Moritani 1 , S Ichihara 1 , M Takahashi 21 Nagoya Medical Centre, 2 Nagoya University Graduate School ofMedicineAims: Breast cancer can be classified into several subtypes based on geneexpression profiling. Basal-like carcinoma (BLC) has a triple negativephenotype that lacks the estrogen receptor, progesterone receptor and humanepidermal growth factor receptor 2, and has myoepithelial propaties. We haverecently reported that CD109, a glycosylphosphatidylinositol (GPI)-anchoredprotein, is a new breast myoepithelial marker. CD109 expression wasinvestigated in invasive ductal carcinomas (IDCs) of the breast byimmunohistochemistry.Methods and results: 88 breast carcinomas of formalin-fixed, paraffinembeddedwere obtained and immunostained with anti-CD109, high molecularweight cytokeratin (HMW-CK: CK1/5/10/14), CK5/6, calponin, Vimentin andp63 antibodies respectively and statistically analyzed. CD109 was detected in18 of 30 basal-like breast carcinomas (BLCs) but not in other types of 53 IDCs(non-BLCs). Statistical analysis revealed that the CD109-positive group in allIDCs cases was significantly associated with a high histological grade, highfrequency of cell mitosis, high nuclear atypia, poor tubule formation, high MIB-1 positive ratio. The percentage of CD109-positive tissues (18/30, 60%) inBLCs was higher than those of other myoepithelial markers including p63(7/30, 23%), calponin (10/30, 33%) and vimentin (10/30, 33%). Although itwas lower than that of HMW-CK (28/30, 93%), CK5/6 (19/30, 63%), HMW-CK was also positive in 28% of non-BLCs and CK5/6 positive in 2% of non-BLCs.Conclusion: These findings indicate that CD109 is a useful marker for BLCs.Summer Meeting (194 th ) 1–4 July 2008 Scientific Programme37