The Technical Issues (What s your protocol?)

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Ira McCormick
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1 The Use of Immunohistochemistry in Prostate Needle Core Biopsies Uses of Immunohistochemistry 2009 Current Issues in Anatomic Pathology May 30 th San Francisco, CA Confirm your diagnosis of cancer Histologically subtle patterns Work-up small atypical foci Jesse K McKenney, MD Director, Urologic Pathology Overview Histology lab decisions Routine protocol Available immunostains Interpretation Real mimic of cancer Examples The Technical Issues (What s your protocol?) 1

2 Preparing Slides for Immunohistochemistry Unstained Interval Levels 1) No prophylactic measures -- Order stains on new levels from block -- De-stain H&E with atypical glands L1 L2 L3 L4 L5 2) Saved unstained interval levels Comparison of Methods Hameed and Humphrey Am J Clin Pathol 2009;131: Routine Deeper Original H&E Technical Risk Extra Work Lose Focus Extra Chances 682 prostate needle core cases (n=38) Ordered stains on interval levels and recut levels De/Re Interval Levels Loss of atypical focus 3 interval (8%) 19 recuts (50%) 2

3 Unstained Interval Levels L1 L2 L3 L4 L5 The Stains Immunostains Cytokeratin 34ßE12 Basal cell markers Cytoplasmic Cytokeratin 34ßE12 (CK903) Cytokeratin 5/6 Nuclear p63 AMACR/P504S 3

4 p63 Cocktails p63/ CK 34ßE12 cocktail Anecdotal cases of basal cell staining with one marker but not the other in individual cases Basal Cell Markers: Summary Sensitivity p63 > CK 34ßE12 p63/ CK 34ßE12 cocktail Better intensity Better quality Two for one Interpreting Basal Cell Markers The basal cell layer is often incomplete Some benign prostate glands can be negative (5-23% in reported studies) Rules that I follow: Morphology driven staining Patchy non-circumferential staining is sufficient evidence of benignity A collection of suspicious glands should be interpreted as a whole 4

5 Population of crowded glands: probable partial atrophy Partial atrophy: population interpreted together Entrapped benign glands with cancer AMACR (P504S/Racemase) Amino acid enzyme involved in fatty acid oxidation Found to be selectively over-expressed in prostate cancer by gene microarray studies in 2000 Antibodies to AMACR are available Many good studies reporting sensitive marker of malignant prostate glands 5

6 Prostate Cancer AMACR/Racemase/P504S AMACR Problems Granular cytoplasmic Luminal/Apical Circumferential Immunoreactivity in benign glands Benign, NOS (2-36%) Atrophy (4-36%) Partial atrophy (50%) Adenosis (18%) Nephrogenic adenoma (35-58%) AMACR/p63 cocktail Cytoplasmic AMACR staining in benign glands AMACR 6

7 AMACR Problems AMACR/p63 Cocktail Immunoreactivity in carcinoma Overall (82-95%) Pseudohyperplastic (70-77%) Foamy (62-72%) Atrophic (70%) Shown to be equivalent to using both antibodies separately Advantage in focal lesions Only one slide is needed Hameed O, Sublett J, Humphrey PA. Am J Surg Pathol 2005;29: Most Common Problems The Problematic Lesions Benign (Pseudomalignant) Partial atrophy Carcinoma (Pseudobenign) Pseudohyperplastic carcinoma Foamy carcinoma Atrophic carcinoma 7

8 Partial Atrophy Partial Atrophy Most common benign mimic of prostate cancer (Herawi et al. AJSP 2005;29;874-80) Earliest phase of atrophy (nuclei more spaced apart and less basophilic) of prostatic adenocarcinoma! Variable loss of cytoplasm Nucleoli may be present (15%) Crowded We glands see with pale everyday. cytoplasm and disorganized appearance Partial atrophy can be the closest mimic Oppenheimer JR, Wills ML, Epstein JI. Partial atrophy in prostate needle cores: another diagnostic pitfall for the surgical pathologist. Am J Surg Pathol 1998;22:440-5 Partial Atrophy Partial Atrophy 8

9 Subtle Variants of Gleason Prostate Carcinoma (Pseudo-Benign) Pseudohyperplastic Carcinoma Pseudohyperplastic Foamy Atrophic Pseudohyperplastic CA Normal Prostate Pseudohyperplastic Carcinoma 9

10 Pseudohyperplastic Carcinoma Foamy Carcinoma Foamy Carcinoma Atrophic Carcinoma 10

11 Atrophic Carcinoma Admixed with Conventional Foamy/Atrophic Carcinoma Using the Stains 11

12 CK 34ßE12 My Diagnosis Benign prostatic glands and stroma 12

13 AMACR/p63 My Diagnosis Prostatic adenocarcinoma, Gleason score 6 (3+3) AMACR/Basal cell cocktail 13

14 My Diagnosis Atypical small acinar proliferation, highly suspicious for carcinoma (S/C) Comment: There is a small gland proliferation present in biopsy right apex consisting of two glands with morphologic and immunohistochemical highly suspicious for carcinoma. Goldstein NS, Begin LR, Grody WW, Novak JM, Qian J, Bostwick DG. Minimal or no cancer in radical prostatectomy specimens. Report of 13 cases of the "vanishing cancer phenomenon". Am J Surg Pathol 1995 Sep;19(9): My Diagnosis Prostatic adenocarcinoma, Gleason score 6 (3+3) 14

15 AMACR/Basal cell cocktail My Diagnosis Prostatic adenocarcinoma, Gleason score 6 (3+3) AMACR/p63/CK34BE12 15

16 My Diagnosis Benign prostatic glands and stroma with radiation atypia AMACR/Basal cell cocktail My Diagnosis Atypical small acinar proliferation, highly suspicious for carcinoma (S/C) Comment: There is a small gland proliferation present in biopsy left base consisting of two glands with morphologic and immunohistochemical highly suspicious for carcinoma. 16

17 Rule Out Pseudohyperplastic Carcinoma Rule Out Pseudohyperplastic Carcinoma My Diagnosis Benign prostatic glands and stroma 17

18 Summary My approach Rule out benign mimics Know the pseudo-benign variants of cancer Don t rule out cancer for the wrong reason Use immunohistochemistry Not blindly (specificity issue) Confirmation e.g., Pseudohyperplastic or foamy Rule out benign with a few atypical glands Deciding on a Histology Protocol In my opinion, cutting and saving interval unstained slides is the best method Retrospective and prospective studies Choosing Your Immunostains: Basal Cell Markers Choosing Your Immunostains: Do you need AMACR? p63 is most sensitive basal cell marker CK 34ßE12 is also acceptable CK 5/6 probably shouldn t be used at present p63/ CK 34ßE12 cocktail is a good alternative How often do you use them in your practice? Is it cost effective to have one stain for prostate only? CK 34ßE12 can also be used as your high molecular weight cytokeratin Is AMACR standard of care? Do you have dual chromagen capability? AMACR/p63/HMWCK cocktail can be very useful Does your case volume rationalize a stain only used in prostate biopsies? 18

19 Using the Term ASAP Not simply for funny looking glands When benign lesions are excluded, ASAP identifies a group of patients whose pretherapy work-up and risk assessment will benefit from additional biopsies Generally, should not use ASAP if any basal cells The Use of Immunohistochemistry in Prostate Needle Core Biopsies Jesse K McKenney, MD Director, Urologic Pathology Stanford University Medical Center 19

The Use of Immunohistochemistry for Diagnosis of Prostate Cancer

Clinical Urology Immunohistochemistry for Diagnosis of Prostate Cancer International Braz J Urol Vol. 36 (5): 583-590, September - October, 2010 doi: 10.1590/S1677-55382010000500008 The Use of Immunohistochemistry