肾脏肿瘤免疫组化，越看越糊涂，糊涂得连良恶性有时候都分不开，儿童肾肿瘤中的诊断问题，在鉴别诊断中，PAX2也是不错的选择。PAX2 Expression in Wilms Tumors and Other Childhood Neoplasms
(Am J Surg Pathol 2011;35:1186–1194)Abstract: PAX2 plays an important role in kidney development;
although small studies have demonstrated PAX2 expression in
Wilms tumors (WT), comprehensive studies on formalin-fixed
tissue are lacking. Thus, we systematically evaluated PAX2
immunohistochemical staining in a retrospective study of
pediatric WT, as compared with other pediatric tumors. We
stained formalin-fixed, paraffin-embedded sections from 39 WT,
6 nephrogenic rests, 8 non-Wilms renal tumors, and 43 nonrenal
pediatric small round cell tumors with 2 different PAX2
polyclonal antibodies. PAX2 demonstrated strong, diffuse
staining of epithelial and blastema components of WT (97%
of cases). PAX2 stained WT stroma in fewer cases (23%), but
80% of anaplastic foci were positive. Nephrogenic rests, 1 case of
metanephric adenoma, and 1 pediatric renal cell carcinoma were
also PAX2 positive; other pediatric renal tumors were negative.
Neuroblastoma, primitive neuroectodermal tumor/Ewings, and
T-cell acute lymphoblastic lymphoma (ALL) were PAX2 negative.
However, PAX2 weakly stained some cases of B-cell ALL
rhabdomyosarcoma (RMS) was also stained, especially alveolar
RMS (83%), with less staining of embryonal RMS (13%). One of
the antibodies also stained maturing myoid cytoplasm of WT and
RMS. This study shows that PAX2 is a sensitive marker of WT
(sensitivity 97%), but PAX2 shows weak-to-moderate-intensity
nuclear staining of RMS and B-cell ALL, somewhat limiting its
utility. However, PAX2 may be a helpful marker in certain
diagnostic situations. We speculate that RMS and B-cell ALL