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Pathology Journal Reading. Presented by Intern 曾德朋. Objective. To identify the role of cytokeratins in distinguishing intraductal papilloma from papillary ductal carcinoma in situ. Introduction. Papillary breast tumors: Proliferated mammary epithelium projects into duct lumen
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Pathology Journal Reading Presented by Intern 曾德朋
Objective • To identify the role of cytokeratins in distinguishing intraductal papilloma from papillary ductal carcinoma in situ
Introduction • Papillary breast tumors: • Proliferated mammary epithelium projects into duct lumen • Intraductal papilloma • Preinvasive papillary ductal carcinoma in situ (DCIS) • Sometimes difficult to distinguish: overlapping microscopic appearances
The need to separate them… • Distinct biologic behavior • Papillary DCIS potentially progressing to invasive cancer • Surgical extirpation • Benign papillomas • Discharged from clinical follow up
Cytokeratins (CK) • Fundamental markers of epithelial differentiation • Cell type & differentiation status • Previous studies: • CK5/CK6, 34BE12 and CK14 in distinguishing usual epithelial hyperplasia from atypical ductal hyperplasia (ADH) and DCIS • Presence of myoepithelial cells • Preserved in benign papillomas, scant in papillary DCIS • Muscle actin and 34BE12 (less specific)
In this study… • Detail the expression of three CK antibody preparation • CK5/6 • CK14 • 34BE12 (recognizing CKs 1, 5, 10 and 14)
Aim of this study… • determining their role (CKs) in differentiating the benign papilloma from malignant in situ papillary carcinoma • Scant literature that specifically addresses papillary lesions • previous work focusing on proliferative breast lesions as a generic group versus DCIS • Semiquantitative criteria of immunoscores to evaluate the CKs • Ascertain the findings by extrapolating to a separate group
Materials and Methods • Patients and tumors • 50 excision biopsies of papillary breast lesions (25 intraductal papillomas and 25 papillary DCIS) • Department of Pathology, Singapore General Hospital, 2002~2003 • Variously reported by 14 general surgical pathologists - initially • Diagnostic review and assignment to papilloma and papillary DCIS by Pathologist P.H.T • Results were all in concordance with initial diagnosis
Materials and Methods… • Cont… • Intraductal papillomas (25 cases) • Age: mean 44.1 y/o (22-78 y/o) • Epithelial hyperplasia of mild to florid degree • No atypical ductal hyperplasia • Papillary DCIS (25 cases) • Age: mean 57.4 y/o (35-78 y/o) • No invasive elements present
Materials and Methods… • Cont… • 43 Hong Kong cases • As to confirm the result with a separate distinct cohort • Initial diagnosis: 10 general surgical pathologists • Histologically reviewed by pathologist G.M.T • Cases: age: mean 52.5 y/o • 1993 ~ 2001 • Excision biopsies 36 cases • Core biopsies 7 cases • Submitted for CK immunohistochemical staining at SGH, without prior discussion
Materials and Methods… • Cont… • Immunohistochemistry • Human tonsil, squamous cell carcinoma and prostate: positive controls for CK5/6, CK14, and 34BE12, respectively • Normal ducts and ductules in the breast tissues: internal control
Materials and Methods… • Cont… • Scoring of sections • Staining intensity: 0, no staining; 1+, weak; 2+, moderate; 3+, strong • Quantification of positivity (0%~100%) • Estimate of the percentage of stained tumor cells in the lesion • Immunoscores: multiplying the staining intensity with percentage positivity (0~300) • Negative or low (0~50); Moderate (51~100); High (101~200); Very high (201~300)
Materials and Methods… • Cont… • Confocal microscopy • Statistical analysis • Two-tailed t test: differences in immunoreaction between the two sample groups • Positive predictive value: CK immunoscore of <50 • Papillary DCIS • Negaive predictive value: CK immunoscore of >50 • Papilloma • Reevaluate for cases with discrepancies
ImmunoreactionsIntraductal Papillomas and Papillary DCIS (SGH cases)
ImmunoreactionsIntraductal Papillomas and Papillary DCIS (SGH cases) • CK5/CK6 • Papillomas • 72% : moderate to high immunoscores • Papillary DCIS • All: low immunoscores with 10 being completely negative • CK14 • Papillomas • 84% high to very high immunoscores • 16% moderate to low immunoscores • Papillary DCIS • 84% low immunoscores • 16% moderate immunoscores • 34BE12 • Papillomas • 56% high to very high immunoscores • 44% low to moderate • Papillary DCIS • 80% low • 20% moderate (1 case: high positivity)
ImmunoreactionsIntraductal Papillomas and Papillary DCIS (SGH cases) • t test • Staining intensity, precetage positivity, immunoscores for each CK: • all three parameters showed significantly higher in papillomas than DCIS
CK5/CK6 • CK5/CK6 expression in an intraductal papilloma (left panel) and • Papillary DCIS (right panel) • About half of the tumor cells in the papilloma were stained, whereas • tumor cells in DCIS were nonreactive
CK14 • CK14 expression in an intraductal papilloma (left panel) and • Papillary DCIS (right panel) • More than half of the tumor cells in the papilloma were stained, • whereas tumor cells in DCIS were nonreactive
34BE12 • 34BE12 expression in an intraductal papilloma (left panel) and • Papillary DCIS (right panel) • Approximately half of the papilloma tumor cells were stained, • some DCIS tumor cells were also decorated
Results… • Hong Kong cases • Immunoscores objectively determined by PHT (SGH) • CK5/CK6 corroborated • Papilloma 89.3% • Papillary DCIS 86.7% • CK14 • Papilloma 92.9% • Papillary DCIS 86.7% • 34BE12 • Papilloma 96.4% • Papillary DCIS 33.3%
Discussion • Cytoskeleton • Microtubules, microfilaments and intermediate filaments (CKs belong to one of 5 classes of intermediate filaments) • CKs: cytoplasmic scaffold • Sustain mechanical and nonmechanical stresses • Participation in the response to stress, cell signaling and apoptosis • To date: 20 CKs (12: acidic type I; 8 neutral-basic type II)
Discussion • Normal resting mammary gland • Epithelium lining • Inner luminal epithelial (LE) cells • CKs 7, 8, 18, 19 • Outer myoepithelial (ME) cells • CKs 5, 14, 17
Discussion • Previous studies • Monoclonal antibodies specific against simple and/or basal type CKs • Benign and malignant intraepithelial proliferations of breast • Atypical proliferations • Invasive breast carcinomas No study compares the expression of basal-type CKs in papillary tumors
Discussion • Our results • CK14 stained a significantly larger percentage of tumor cells in papilloma • Breast epithelium of proliferating mammary gland • 3 types of cells: immature precursor (CK5/CK6) intermediate (CK5/CK6, CK 8, 14, 18, 19), fully mature (CK14, 18, 19) • Intraductal papilloma • Larger proportion of fully mature cells
Discussion • 34BE12 • Stained more DCIS tumor cells • Recognizes CK1, 10, 5, 14 • CK10 expressed in some LE cells in breast cancers (previous studies)
Discussion • Results applied to a separate distinct cohort of HK cases, confirmation of • Benign papilloma diagnosis 89.3% (CK5/CK6) to 96.4% (34BE12) • Discordant cases: small or core biopsy • ADH case: necessity for microscopic reevaluation • Papillary DCIS (result at odds) • Core biopsy • Invasive component (detect LE as well) • Not as reliable or sensitive as the other 2 CKs • Apocrine nature
In summary • The three CKs can serve as helpful adjunctive markers • Particularly combination of CK5/CK6 and CK14 • 34BE12: low detection rate • Especially in delineation of papillary DCIS • Use of CKs on small lesions, core biopsies, apocrine morphology, and associated invasive cancer need further evaluation