title: Tissue pretreatment with formic acid might lower HercepTest scores in breast cancer.
abstract: Creutzfeldt-Jakob disease and other prion diseases are diseases with yet not well-defined routes of transmission and infection. The safe processing of potentially contaminated tissue material remains a challenge for histologic laboratories. Formic acid pretreatment is considered to be effective in prion inactivation. We evaluated the c-erbB2 and the hormone receptor-status in potentially prion infectious breast cancer tissue after pretreatment with formic acid. Paired breast cancer tissue samples were immunostained with commercially available antibodies against c-erbB2, estrogen receptor, and progesterone receptor with 1 tissue sample of each pair being pretreated with 98% formic acid. Staining was evaluated either according to the HercepTest score or using an immunoreactive score. Additionally, fluorescence in situ hybridization (FISH) analyses were performed for 7 of these cases. Untreated tissues showed strong circumferential staining for c-erbB2 (HercepTest score 3+), whereas the membranous staining of the tissues pretreated with formic acid was significantly weaker. FISH analyses showed no differences in both groups. The hormone receptor expression was not significantly influenced and positivity was maintained in all cases. In breast cancer patients, the pretreatment of tissue with formic acid for prion-decontamination in the case of suspected Creutzfeldt-Jakob disease or other prion diseases can lead to underestimation of the immunohistologically determined c-erbB2 status. In these cases, a c-erbB2-FISH analysis should be performed. For the immunostaining of hormone receptors in breast cancer, formic acid pretreatment can be applied without negative effects on the sensitivity or specificity of the assay.
authors.affiliation: Institute of Pathology, Charité-Universitätmedizin Berlin, Charité Platz 1-3, 10117 Berlin.
authors.forename: Florian R
authors.initials: FR
authors.lastname: Fritzsche
authors.forename: Glen
authors.initials: G
authors.lastname: Kristiansen
authors.forename: Andreas
authors.initials: A
authors.lastname: Boesl
authors.forename: Mick
authors.initials: M
authors.lastname: Burkhardt
authors.forename: Stefan
authors.initials: S
authors.lastname: Pahl
authors.forename: Anja
authors.initials: A
authors.lastname: Dankof
authors.forename: Manfred
authors.initials: M
authors.lastname: Dietel
authors.forename: Edgar
authors.initials: E
authors.lastname: Dahl
mesh_terms: D001943:Breast Neoplasms / Q000737:chemistry / Q000150:complications / Q000235:genetics / Q000473:pathology*; D007562:Creutzfeldt-Jakob Syndrome / Q000150:complications*; D005069:Evaluation Studies as Topic; D005260:Female; D005561:Formates; D006801:Humans; D007150:Immunohistochemistry; D017404:In Situ Hybridization, Fluorescence; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000032:analysis* / Q000235:genetics; D011960:Receptors, Estrogen / Q000032:analysis; D011980:Receptors, Progesterone / Q000032:analysis; D012680:Sensitivity and Specificity; D013048:Specimen Handling / Q000379:methods
chemical_list: D005561:Formates; D018719:Erb-b2 Receptor Tyrosine Kinases; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; C030544:formic acid