High endogenous avidin binding activity: an inexpensive and readily available marker for the differential diagnosis of kidney neoplasms

Abstract

It has been documented that some tissues, such as salivary gland, liver, cardiac and skeletal muscles and kidney, have high level endogenous biotin or endogenous avidin binding activity (EABA). Limited data is available on EABA in renal cell neoplasms. A tissue microarray (TMA) was constructed that included oncocytoma (n=30), chromophobe renal cell carcinoma (RCC) (n=18), clear cell RCC (n=45), clear cell RCC with granular/eosinophilic (G/E) features (n=19), papillary RCC (n=21), papillary RCC with G/E features (n=29) and benign renal tissues (n=31). The TMA slides were stained with or without biotin blocker and analyzed using the automated cellular imaging system (ACIS(R)). Without biotin blocker, a high positive rate of EABA was found in oncocytoma (56/60, 93%) and normal renal tubules (46/60, 77%). A moderate positive rate of EABA was found in clear cell and papillary RCCs with G/E features (13/39, 33% and 19/55, 35%, respectively). Chromophobe RCC and RCC without G/E features had essentially no EABA. With biotin blocker, benign renal tissue and clear cell RCC were negative for EABA; but a significant number of renal oncocytoma (29/60, 48%) and a few papillary RCC with G/E features (5/52, 10%) remained positive for EABA. In conclusion, high EABA may be used to differentiate oncocytoma from chromophobe RCC, and the staining results must be interpreted with caution when avidin-biotin detection system is used in diagnosing renal neoplasms.

Keywords: Oncocytoma; chromophobe renal cell carcinoma; endogenous avidin binding activity (EABA).

Figure 1

Endogenous avidin binding activity (EABA) in renal neoplasms. A pair of panels (objective magnification 4× and 40×) for each group are shown. EABA was detected in 93% of oncocytomas (1A and 1B); 77% of normal kidney tubules (1C and 1D); in 35% of papillary RCCs with G/E features (1E and 1F); in 33% of clear cell RCCs with G/E features (1G and 1H). Weakly positive EABA was detected in two cores of chromophobe RCC (1I and 1J).

Figure 2

Endogenous biotin blocker (endogenous biotin blocking kit, Ventana Medical, Inc) has limited power in blocking EABA in renal neoplasms with high EB content. A pair of panels (objective magnification 4× and 40×) for each group are shown. With EB blocker, EABA was detected in 48% of oncocytomas (2A and 2B) and in 10% of papillary RCCs with G/E features (2C and 2D).