Amylase α-1A (AMY1A)

Abstract

Chromophobe renal cell carcinoma (ChRCC) and oncocytoma present with a perplexing overlap of morphologic and immunohistochemical features. ChRCC have deletions in the 1p21.1 region including the amylase α-1A gene (AMY1A). No such deletions are found in oncocytoma. Instead, oncocytomas shared other deletions on chromosome 1: 1p31.3, 1q25.2, and 1q44. We performed AMY1A immunostaining on 75 oncocytomas (57 tissue microarray [TMA] cores, 18 whole slides) and 54 ChRCCs (20 TMA cores, 34 whole slides). Staining was assessed using the H-score method. The intensity was graded as follows: no staining=0, weak=1, moderate=2, and strong=3. The AMY1A immunostain preferentially stained the distal tubules and collecting ducts of normal kidney. All oncocytomas (100%) expressed AMY1A with an H-score that varied from 100 to 300 (mean 205). Mild to moderate heterogeneity in staining intensity was noted within a given oncocytoma. For oncocytomas, 87% (65/75) cases had H-scores of at least 120 with a mean score of 221. Notably, the 13% (10/75) of oncocytoma cases that had an H-score of 100 were derived from the TMA. A total of 87% (47/54) of the ChRCC cases were negative for the AMY1A immunostain. Of the ChRCC cases, 4% (2/54) showed very weak cytoplasmic staining (H-score of 70 each), which was less than the lowest H-score of oncocytoma cases. All 5 cases of ChRCC, which showed an H-score of 100 or more, were referred to as eosinophilic variants of ChRCC. Three of these 5 cases showed a very nondescript, diffuse staining of the cytoplasm. Two of these 5 cases showed an H-score of 130. We think that as the staining pattern of these 2 cases is similar to that of oncocytoma, they should be put in a category of renal oncocytic neoplasms favoring oncocytoma. This result shows that AMY1A staining could be very helpful in further classifying even a subset of the eosinophilic variants of ChRCC. The difference between ChRCC and oncocytoma was statistically significant (χ2 test, P<0.0001). All cases of clear cell RCC and papillary RCC were negative for AMY1A expression. Overall, sensitivity and specificity of AMY1A staining for oncocytoma was 100% (95% confidence interval, 0.95–1.00) and 96.75% (95% confidence interval, 0.93–0.99), respectively. Similarly, the sensitivity and specificity for distinguishing oncocytoma from ChRCC was 100% (95% confidence interval, 0.95–1.00) and 90.74% (95% confidence interval, 0.80–0.97), respectively. These data show that the novel marker AMY1A can be of great diagnostic utility when trying to differentiate ChRCC (classic and eosinophilic variant) and oncocytoma.

BSND and ATP6V1G3

“…We next examined the expression status of BSND and ATP6V1G3 in renal oncocytoma, since this benign tumor often shares common morphological and immunophenotypic features with chromophobe RCC. 30 , 31 Immunohistochemical analysis for the BSND and ATP6V1G3 proteins revealed strong diffuse positivity for both in most of the renal oncocytoma specimens (13/14 cases, 92.9%, for both proteins) (Figure 2 M–O and Table 3 ), suggesting that BSND and ATP6V1G3 are immunohistochemical markers for renal oncocytoma as well as chromophobe RCC.…”

The Role of CK7, S100A1, and CD82 (KAI1) Expression in the Differential Diagnosis of Chromophobe Renal Cell Carcinoma and Renal Oncocytoma

“…15 Many immunohistochemical markers such as CK7, kidney-specific cadherin, CD10, epithelial membrane antigen, RCC marker, MOC31, S100A1, leptin, FXYD2, CD63, transforming growth factor beta-1, EpCAM, parvalbumin, Wnt5a, caspase 3, caveolin-1, RB1, ARPP, and amylase 1 alpha have been investigated in the differential diagnosis. 4,11,12,[16][17][18][19][20][21][22][23] Among these markers, CK7 has become the most effective and the most recommended marker in differential diagnosis between chromophobe RCCs and oncocytomas. However, in some cases, CK7 alone may not be sufficient for this distinction.…”

Proteômica de biopsias líquidas (sérica e urina) como biomarcadores nos adenocarcinomas colorretais

“…• Alfa-amilase Apesar de na literatura não apresentar ligação ao CCR, esta proteína é por vezes citada como marcador de processos inflamatórios e alguns tumores, como mama, pulmão, tireoide, ovário, plasmocitomas pulmonares e mamárias [103,104].…”