Immunohistochemical stains for basal cells, such as HMWCK
or more recently p63 are currently used in the diagnosis of focal prostate cancer but there are limitations in their use as negative staining for basal cell markers is by itself not diagnostic of carcinoma and also due to technical reasons these stains may be falsely positive thus it is necessary to interpret negative staining in an atypical focus in light of positive staining in adjacent benign glands which is used as an internal positive control.
Permanent sections and immunohistochemical profile with positive immunoreactivity for HMWCK
, vimentin and CD-99 as well as negative immunostaining for LCA, desmin, NSE, and chromogranin allowed the pathologist to distinguish the PNET from other small round cell tumors (figure 1).
A useful panel for this distinction is CD10, CK7, RCC marker, mesothelin and HMWCK
(clone 34 E12).
(66-69) When a predominantly spindle cell lesion with limited tissue availability is encountered in the bladder, an immunohistochemical panel composed of ALK-1, SMA, desmin, cytokeratin (AE1/AE3), p63, and HMWCK
or CK5/6 is potentially helpful (Table 5).
(CK903, clone 340E12) is a well-known basal cell marker.
In the assessment of atypical papillary lesions (ADH/DCIS involving benign intraductal papilloma or papillary DCIS), immunohistochemical evaluation of the expression of HMWCK
is a valuable adjunct, in which benign papillary lesions exhibit strong, mosaic reactivity throughout the lesion in 88% to 100% of cases, and atypical papillary lesions are nonreactive, indicating a clonal proliferation of luminal epithelial cells in 80% to 100% of cases.
(1-13) In addition, p63 has often been used in conjunction with high-molecular-weight cytokeratin (HMWCK
) and a-methylacyl coenzyme A racemase (AMACR) in prostate biopsies.
The immunoprofile of PSCN may be identical to that of IMT (low-weight cytokeratin, SMA, desmin positive, and HMWCK
and p63 negative).
These atypical glands were diffusely strongly positive for p63 in the secretory cells (ie, not in a basal cell distribution), negative for high-molecular-weight cytokeratin (HMWCK
), and positive for [alpha]-methylacyl coenzyme A racemase (AMACR) (Figure 1, D).
Diagnostic utility of a-methylacyl CoA racemase (P504S) & HMWCK
in morphologically difficult prostate cancer.
(22) Immunohistochemically, they stain for p63 and high-molecular-weight cytokeratin (HMWCK
), which is helpful diagnostically and serves to differentiate benign glands and high-grade prostatic intraepithelial neoplasia from prostatic adenocarcinoma.
Extended Special Other Stains Immunohistochemistry Findings Mucicarmine, PAS HMWCK
-; desmin, EM rare +, colloidal S100, vimentin - Fe + NA NA Cytology NA NA EM, cytology Mucicarmine, PAS Vimentin +; Ulex EM -, Alcian blue +w +; AFP, CEA - PAS/PAS-D -, Desmin, CEA, NA colloidal Fe - vimentin -; EMA +f NA Vimentin + NA NA Vimentin + NA NA NA NA NA NA NA NA NA NA NA NA NA NA Vimentin +, LCA - Cytology, EM