[1093] Significantly Decreased p63 and p40 Expression in Urothelial Carcinoma (UC) with Glandular Differentiation (GD)

Bing Zhu, Xiaoqi Lin, Stephen M Rohan, Celina Villa, Elizabeth Gersbach, Ximing Yang. Northwestern University Feinberg School of Medicine, Chicago, IL

Background: UC has a great capacity for morphological plasticity. GD is the second most common form of divergent differentiation. UC with GD is associated with aggressive clinical behavior. MPUC is a variant of UC that also has aggressive behavior. Some authors have suggested that MPUC might represent a form of GD. We investigated p63 and p40 immunohistochemistry (IHC) patterns in MPUC and UC with/without GD.
Design: IHC for p63 and p40 was performed on paraffin embedded tissue sections of 62 cases of high grade UCs (HGUC) of different stages (46 ≥T2, 16 < T2) with/without GD, 16 low grade UCs (LGUC) (14 Tis, 2 T1 with GD) and 20 MPUCs (16 ≥T2, 4 Results: See table1 and table2.

Table1. p63 and p40 expression in MPUC and UC with/without GD.
MarkerPositivityMPUC (n=20)HGUC≥T2 (n=46)GD in HGUC ≥T2 (n=16)HGUC GD in HGUC LGUC (n=16)
p63Positive Cases (%)0.073.937.593.840.0100.0
 Positive Cells (%)0.0 ± 0.030.0 ± 30.86.5 ± 11.055.0 ± 24.513.0 ± 22.689.4 ± 3.1
 P Value< 0.001*< 0.01< 0.001 
p40Positive Cases (%)10.093.582.3100.080.0100.0
 Positive Cells (%)0.5 ± 1.660.0 ± 29.418.2 ± 18.660.6 ± 23.620.5 ± 23.992.8 .± 5.5
 P Value< 0.001*< 0.01< 0.001 
Chi-Square test and Student T test. *: MPUC vs. other groups.



Table2. p63 and p40 expression in MPUC and UC with/without GD component of all the cases studied.
PositivityMPUC (n=20)HGUC (n=69)GD in HGUC (n=32)LGUC (n=42)P value
p63 positive tumor cells (%)0.0 ± 0.037.1 ± 30.99.0 ± 16.786.1 ± 6.0P1<0.001, P2=0.017, P3<0.001
p40 positive tumor cells (%)0.5 ± 1.551.4 ± 28.216.9 ± 20.189.8±5.8P1<0.001, P2<0.001, P3<0.001
Student t test. P1: MPUC vs GD in HGUC; P2: GD in HGUC vs. HGUC; P3: GD in HGUC vs. LGUC.


Conclusions: Our study revealed a loss of p63 expression in MPUC and decreased p63 expression in high grade and high stage of conventional UC. p40 expression was only seen in a small subset of cells in rare MPUC cases and significantly decreased p40 expression was seen in HGUC. Expression of both p63 and p40 was significantly decreased in MPUC and UC with GD. The similar staining pattern seen in MPUC and UC with GD is consistent with the idea that these two UC variants may be related. Importantly, when using p63 or p40 to confirm the urothelial origin of a carcinoma, it is important to realize that MPUC and areas of GD in UC often do not express these markers.
Category: Genitourinary (including renal tumors)

Wednesday, March 6, 2013 9:30 AM

Poster Session V # 151, Wednesday Morning

 

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