immunohistochemical staining of precursor forms of prostate-specific antigen (propsa) in metastatic...
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Immunohistochemical Staining of Precursor FormsImmunohistochemical Staining of Precursor Formsof Prostate-specific Antigen (proPSA) in Metastaticof Prostate-specific Antigen (proPSA) in Metastatic
Prostate CancerProstate Cancer
Anil V. Parwani, MD, PhD,* Cameron Marlow, BS, Angelo M. DAnil V. Parwani, MD, PhD,* Cameron Marlow, BS, Angelo M. Demarzo, MD, PhD, Stephen D. Mikolajczyk, PhD, Harry G. Rittemarzo, MD, PhD, Stephen D. Mikolajczyk, PhD, Harry G. Ritt
enhouse, PhD, Robert W. Veltri, MD, and Theresa Y. Chanenhouse, PhD, Robert W. Veltri, MD, and Theresa Y. Chan Am J Surg Pathol 2006;30:1231–1236
指導老師 : 陳志榮老師 報告者 :Intern 陳嘉哲
Introduction Introduction
Prostate carcinoma: * most common carcinoma in American
man. * second leading cancer-related deaths i
n the United States. * In the year 2005 in the United States 230,000 new cases of prostate cancer 230,000 new cases of prostate cancer 30,000 deaths due to prostate cancer30,000 deaths due to prostate cancer
Introduction Introduction
Prostate-specific antigen (PSA) * As a tumor marker for prostate cancer* a serine protease produced by both pr
ostate epithelial and cancer cells.* normal function: liquify gelatinous sem
en after ejaculation, allowing spermatazoa to more easily "swim" through the uterine cervix.
Introduction Introduction
Precursors of prostate-specific antigens: Precursors of prostate-specific antigens: * * 244-amino acid proenzyme244-amino acid proenzyme * * more concentrated in prostate cancer more concentrated in prostate cancer
than in benign tissuethan in benign tissue * * a more cancer-specific markera more cancer-specific marker
Introduction Introduction Authors’ previous studies: Authors’ previous studies: ** Immunohistochemical staining (IHS) :Immunohistochemical staining (IHS) :
monoclonal antibodies (mABs) against proPSA with a truncated proleader peptide containing 2 amino acids ([-2]pPSA), and against native proPSA ([-5/-7]pPSA). 2 aa = serine, arginine
* mABs to proPSA are specific for benign and malignant prostatic tissue.
Introduction Introduction
* ProPSA remained uniform among the different tumor grade.
* PSA staining intensities and Gleason score
had a strong inverse correlation.* Metastatic prostate carcinoma may sho
w negative PSA staining.
IntroductionIntroduction
The objective of this study:* compare the IHS patterns of proPSA wit
h that of PSA and prostatic acid phosphate (PAP) on a series of metastatic prostate carcinoma cases.
* Find the utility of proPSA in these lesion
Materials and MethodsMaterials and Methods
Tissue Microarray (TMA) Design:Tissue Microarray (TMA) Design:* * 74 cases( metastatic prostate carcinoma):74 cases( metastatic prostate carcinoma): Soft tissue / bone N= 40 Soft tissue / bone N= 40 lymph node N= 34 lymph node N= 34 from the surgical pathology files of The
Johns Hopkins Hospital. (nonhormone refractory tumors)
* 3 cores of each specimen - TMA
Tissue Microarray (TMA) DesigTissue Microarray (TMA) Designn
All the metastatic tumors: higher grade, poorly differentiated carcinomas.
Control tissues:* primary prostate adenocarcinoma with G
leason scores ranging from 6 to 7 (n=20)* normal prostatic tissue (n=20)* normal tissue from brain, skin, colon, and
other 14 tissues to the TMA.
Immunohistochemistry
IHS: IHS: deparaffinized TMA slides using a standard streptavidin horseradish-peroxidase conjugate.
A purified mouse immunoglobulin G mAB, PS2P446 proPSA with both the 7 aa and 5 aa leader peptides ([-5/-7]pPSA, Beckman Coulter, San Diego, CA).
Immunohistochemistry
A purified mouse immunoglobulin G mAB, PS2373.3, which recognizes proPSA with a 2 aa leader peptide ([-2]pPSA, Beckman Coulter). pPSA form
These proPSA mABs had less than 0.2% cross-reactivity to PSA or to each other.
These proPSA mABs: research use.
Immunohistochemistry Evaluation of metastatic prostate carcinEvaluation of metastatic prostate carcin
omas: intensity and extent of IHS. omas: intensity and extent of IHS. ** cocontrolled by human eyentrolled by human eye
The intensity of staining was categorized as weak, moderate, or strong.
A numerical score assigned to each spot on the TMA.
0 for negative ; 1 for weak ; 2 for moderate ; 3 for strong
Immunohistochemistry
a mean score was calculated for each sample present in triplicate.
The mean score : 0 to 0.5 = negative ; 0.5 to 1.5= weak, 1.5 to 2.5 = moderate ; 2.5 or greater = strong.
Immunohistochemistry Extent of staining: Extent of staining: diffuse ( more than 50% of cells)diffuse ( more than 50% of cells) patchy ( less than 50% of cells)patchy ( less than 50% of cells) 5 cases : 5 cases : insufficient tissue on more than 2 of t
he 3 spots can’t be evaluated. 9 cases : lack of tissue on PSA and PAP stains
only ProPSA. Total 60 cases all 4 mABs were evaluated.
Results Results
ResultsResults
There were minor differences between the
4 antibodies in extent of staining. * [-5/-7]pPSA and PSA : the most numb
er of cases with diffuse staining (75%, 69%), the least number of cases with patchy staining (25% and 31%).
ResultsResults
[-5/-7]pPSA showed the most number of positive cases (98%) compared with [-2] pPSA (80%), PSA (81%), PAP (83%).
strong or moderate staining was seen in 82%, [-5/-7] pPSA, 76% PSA, 39% PAP, and 29% [-2] pPSA.
Seven cases (12%) were negative for both PSA and PAP, but showed staining with [-5/-7]pPSA and/or [-2]pPSA.
Result Result
Only 3 case (5%): Only 3 case (5%): [-5/-7]pPSA was the only positive marker; 2 moderate, and 1 weak.
Only 1 case (2%): [-2]pPSA was the only positive marker; the intensity of this one weak.
ResultResult
There was no staining in prostatic stromal and vascular tissue.
No other tumor types was in this study. Only focal weak cytoplasmic staining wit
h both the proPSA mABs to control thyroid and kidney tissues.
Discussion Discussion
In this article, authors evaluated: proPSA as a diagnostic markers in the detectio
n of metastatic prostatic adenocarcinoma versus PSA and PAP.
PSA shows a decrease in expression from benign epithelium to HGPIN and adenocarcinoma.
(Urology 49: 857–862, 1997.)
Discussion Discussion
A strong inverse correlation between PSA staining intensities and Gleason scores.
(Am J Clin Pathol 117: 471–477, 2002.) The immunoreactivity for pro-PSA appears to r
emain uniform among the different tumor grades.
[-2] proPSA appeared to be preferentially more concentrated in cancer tissue than in benign glands. (Urology. 2003;62:177–181.)
Discussion Discussion
In current study, no difference in the staiIn current study, no difference in the staining pattern of benign gland for 4mABs.ning pattern of benign gland for 4mABs.
In this study, In this study, proPSA [-5/-7] showed the most number of cases with moderate or strong staining (76%) as compared with PSA (56%), PAP (43%) and proPSA [-2] (55%).
Discussion Discussion
a case of poorly differentiated carcinoma from an unknown primary. using PSA or PAP as a diagnostic marker?
In this study, -5/-7 proPSA (native proPSA) may be a better marker than PSA and PAP in metastatic prostate adenocarcinoma,
only 2 cases (3%) being negative for the marker.
Discussion Discussion
PSA is a serine protease, and a major protein in seminal fluid.
PSA is produced by both prostate epithelial cells and prostate cancer and is secreted into prostatic ducts as an inactive 244-amino acid proenzyme (proPSA) which is activated by cleavage of 7 N-terminal amino acids.
(Cancer. 2004;101:894–904.)
Discussion Discussion
PSA either as the free “non-complexed” form or as a complex with alpha1-antichymotrypsin.
Ratio of free to total serum PSA * lower percent free PSA levels correlatin
g with a higher risk of prostate cancer. (JAMA 297: 1542–1547, 1998)
Discussion Discussion
Normally proPSA with a seven amino acid (aa) proleader peptide ([-7]pPSA).
Pro PSA (pPSA), precursor form of PSA, is a component of free PSA in the serum of PCa patients.
ProPSA is differentially elevated in PZ-C, but is largely undetectable in TZ .
(Cancer Res 60: 756–769, 2000.)
Discussion Discussion
ProPSA: ↑ specificity for prostate carcinoma, particularly in the 2 to 4 ng/mL PSA range. (J Urol. 2003;170:2181–2185)
Catalona et al indicated:1. Percent proPSA better than percent free and c
alculated complexed PSA for detecting prostate carcinoma in the PSA range of 2 to 10 ng/mL.
2. Selectivity for detecting more aggressive cancers (Gleason score 7 or greater and/or extracapsular tumor extension.) (J Urol. 2004; 71:2239–2244.)
Discussion Discussion
In the diagnostic range of 4 to 10 ng/mL, PSA has limited specificity for distinguishing early prostatic adenocarcinoma from benign prostatic hyperplasia. (Cancer. 2004;101:894–904.)
Discussion Discussion
Further ideas: use of proPSA as an immuFurther ideas: use of proPSA as an immunohistochemical marker in amount of spnohistochemical marker in amount of specimens from variety of sources includinecimens from variety of sources including cytology specimen.g cytology specimen.
A Truncated Precursor Form of Prostate-specific Antigen Is a More Specific Serum Marker of Prostate Cancer
(CANCER RESEARCH 61, 6958–6963, September 15, 2001)
HK2 and trypsin can activate [-5/-7]pPSA to mature PSA
UROLOGY 62: 177–181, 2003. © 2003
UROLOGY 62: 177–181, 2003. © 2003
SERUM PRO-PROSTATE SPECIFIC ANTIGEN PREFERENTIALLYDETECTS AGGRESSIVE PROSTATE CANCERS IN MEN WITH
2 TO 4 NG/ML PROSTATE SPECIFIC ANTIGEN
Urology Vol. 171, 2239–2244, June 2004
Discussion Discussion
Why does proPSA show greater staining Why does proPSA show greater staining than than [-2] proPSA in metastatic cancer?
Why should we find a better diagnostic marker for malignant prostate cancer?
Maybe we can evaluate proPSA in the serum to detect prostate cancer.