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Product details

Synonyms = BHLHE33

Antibody type = Recombinant Rabbit monoclonal / IgG

Clone = MSVA-403R

Positive control = Kidney: A moderate to strong TFE3 staining should be seen in a fraction of glomerular cells and an at least weak TFE3 staining should be seen in a subset of tubular and collecting duct cells.

Negative control = Colon: TFE3 staining should be absent in epithelial cells (some very faint staining can occasionally occur at the surface).

Cellular localization = Nuclear

Reactivity = Human

 

 

Application = Immunohistochemistry
Dilution = 1:100 – 1:200
Intended Use = Research Use Only

Relevance of Antibody

TFE3 is a Critical regulator of expression of genes involved in lysosomal function.

Biology Behind

The Transcription factor E3 (TFE3) protein is a member of the microphthalmia-associated transcription factor (MITF) family of the basic helix-loop-helix leucine zipper family of transcription factors. It is coded by the TFE3 gene at chromosome Xp11.2. In non-starving, resting cells, TFE3 is primarily cytoplasmic. In case of lack of nutrition or energy stress, TFE3 translocates to the nucleus and becomes active. TFE3 target genes play a role in control of metabolic processes in response to nutrient and energy stress and especially include genes implicated in the control of lysosomal functions, such as endocytosis, phagocytosis, and autophagy. As such, TFE3 is involved in metabolic responses and metabolic homeostasis in various tissues. A subset of 1-5% of sporadic renal cell carcinomas are driven by gene fusions that cause upregulation of one of the microphthalmia-associated transcription factor (MiT) family members TFE3, TFEB, or MITF. These fusion driven cancers may make up for more than 40% of RCCs in children and young adults. TFE3 directly interacts with E2F3 and microphthalmia-associated transcription factor.

Staining Pattern in Normal Tissues

Images describing the TFE3 staining pattern in normal tissues obtained by the antibody MSVA-403R are shown in our “Normal Tissue Gallery”.

 

Brain Cerebrum Some astrocytic cells show faint TFE3 positivity.
Cerebellum
Endocrine Tissues Thyroid Weak to moderate TFE3 staining can be seen in follicular cells.
Parathyroid Some epithelial cells can show faint TFE3 staining.
Adrenal gland Moderate to strong TFE3 staining of cortical cells.
Pituitary gland Moderate staining of a variable number of epithelial cells.
Respiratory system Respiratory epithelium TFE3 staining of (mainly basal) epithelial cells of the respiratory epithelium and of glandular cells can be seen in some samples.
Lung A large subset of pneumocytes and of alveolar macrophages show weak to moderate TFE3 positivity.
Gastrointestinal Tract Salivary glands Few glandular cells may show weak TFE3 staining.
Esophagus A weak TFE3 staining of squamous epithelial cells can occasionally be seen.
Stomach Mucosa epithelial cells are usually TFE3 negative but mucous neck cells may show faint staining.
Duodenum Mucosa epithelial cells are TFE3 negative.
Small intestine Mucosa epithelial cells are TFE3 negative. A very faint TFE3 staining of muscle cells can occur.
Appendix Mucosa epithelial cells are TFE3 negative while few inflammatory cells show a positive staining (macrophages?). A very faint TFE3 staining of muscle cells can occur.
Colon Mucosa epithelial cells may show a faint TFE3 staining in surface epithelial cells while inflammatory cells (macrophages?) may show a positive staining. A very faint TFE3 staining of muscle cells can occur.
Rectum Mucosa epithelial cells are TFE3 negative while few inflammatory cells show a positive staining (macrophages?). A very faint TFE3 staining of muscle cells can occur.
Liver Negative.
Gallbladder A weak TFE3 staining of epithelial cells occurs in few samples (perhaps related to major inflammation).
Pancreas A faint nuclear TFE3 staining can occur in acinar and ductal cells, especially in case of inflammation and fibrosis. Stroma cells can also be TFE3 positive.
Genitourinary Kidney Moderate to strong TFE3 staining of a subset of glomerular cells. Weak TFE3 positivity of a subset of tubular and collecting duct cells. TFE3 staining is often visible in atrophic tubuli.
Urothelium, urinary bladder A faint TFE3 positivity of urothelial cells can occur. A very faint TFE3 staining of muscle cells can occur.
Male genital Prostate Negative.
Seminal vesicles Moderate to strong TFE3 staining of a fraction (or all) epithelial cells.
Testis Moderate TFE3 staining of Sertoli and Leydig cells.
Epididymis Strong TFE3 staining of epithelial cells in the corpus but not in the caput epididymis.
Female genital Breast Negative.
Uterus, myometrium A faint nuclear TFE3 staining can occur.
Uterus, ectocervix Negative.
Uterus endocervix Negative.
Uterus, endometrium A faint nuclear TFE3 staining can occur in glandular cells. Intense TFE3 positivity in decidua cells in case of pregnancy.
Fallopian Tube A weak nuclear TFE3 staining can be seen in epithelial cells of some samples.
Ovary Strong nuclear TFE3 staining of theca interna and of corpus luteum cells. A markedly weaker TFE3 staining can be visible in granulosa cells.
Placenta early Strong TFE3 staining of syncytiotrophoblast cells while TFE3 positivity is markedly weaker for cytotrophoblast and stroma cells. Intense TFE3 positivity in decidua cells.
Placenta mature Strong TFE3 staining of trophoblast cells.
Amnion Moderate to strong TFE3 staining.
Chorion Variable, weak to strong TFE3 staining of chorion cells.
Skin Epidermis A weak TFE3 staining of squamous epithelial cells can occur, especially in the most superficial cell layers.
Sebaceous glands Negative.
Muscle/connective tissue Heart muscle Negative.
Skeletal muscle Negative.
Smooth muscle Some faint TFE3 staining can occasionally be seen.
Vessel walls Some faint TFE3 staining can occasionally be seen.
Fat Negative.
Stroma Some faint TFE3 staining can occasionally be seen.
Endothelium Some faint TFE3 staining can occasionally be seen.
Bone marrow/ lymphoid tissue Bone marrow Few cells show weak staining.
Lymph node Sinusoidal cells (macrophages?) often show a weak TFE3 staining.
Spleen Weak TFE3 staining of sinusoidal cells (macrophages?).
Thymus Weak TFE3 staining of few cells in corpuscles of Hassall’s.
Tonsil A weak TFE3 staining of squamous epithelial cells can occasionally be seen in crypts and on the tonsil surface (especially in the most superficial cell layers).
Remarks In case of inflammation, TFE3 staining ia regularly seen in some inflammatory (probably monocytic) but also epithelial and possibly endothelial cells.

 

These findings are largely consistent with the RNA data described in the Human Protein Atlas (Tissue expression TFE3).

 

Positive control = Kidney: A moderate to strong TFE3 staining should be seen in a fraction of glomerular cells and an at least weak TFE3 staining should be seen in a subset of tubular and collecting duct cells.

Negative control = Colon: TFE3 staining should be absent in epithelial cells (some very faint staining can occasionally occur at the surface).

 

Normal tissue gallery

Staining Pattern in Relevant Tumor Types

Although TFE3 staining is characteristic for a Xp11.2 translocation RCC, TFE3 immunostaining – at variable levels of intensity – can be found in many different tumor types.

The TCGA findings on TFE3 RNA expression in different tumor categories have been summarized in the Human Protein Atlas.

 

 

Cancer tissue gallery

Compatibility of Antibodies

No data available at the moment

Protocol Recommendations

IHC users have different preferences on how the stains should look like. Some prefer high staining intensity of the target stain and even accept some background. Others favor absolute specificity and lighter target stains. Factors that invariably lead to more intense staining include higher concentration of the antibody and visualization tools, longer incubation time, higher temperature during incubation, higher temperature and longer duration of the heat induced epitope retrieval (slide pretreatment). The impact of the pH during slide pretreatment has variable effects and depends on the antibody and the target protein.

 

All images and data shown here and in our image galleries are obtained by the manual protocol described below. Other protocols resulting in equivalent staining are described as well.

 

Manual protocol

Freshly cut sections should be used (less than 10 days between cutting and staining). Heat-induced antigen retrieval for 5 minutes in an autoclave at 121°C in pH 7,8 Target Retrieval Solution buffer. Apply MSVA-403R at a dilution of 1:150 at 37°C for 60 minutes. Visualization of bound antibody by the EnVision Kit (Dako, Agilent) according to the manufacturer’s directions.

Potential Research Applications

  • The prognostic role of variable TFE3 expression levels in RCCs without TFE3 fusions need to be investigated.
  • The diagnostic and prognostic relevance of TFE3 expression in other tumors and in preneoplastic disease needs to be investigated.

Evidence for Antibody Specificity in IHC

There are two ways how the specificity of antibodies can be documented for immunohistochemistry on formalin fixed tissues. These are: 1. Comparison with a second independent method for target expression measurement across a large number of different tissue types (orthogonal strategy), and 2. Comparison with one or several independent antibodies for the same target and showing that all positive staining results are also seen with other antibodies for the same target (independent antibody strategy). 

 

Orthogonal validation: For proteins such as TFE3 which are expressed in virtually all tissues but restricted to specific cell types and cell compartments, orthogonal validation is not suited. However, the comparison of MSVA-403R immunostaining data with RNA expression data from three independent RNA screening studies, including the Human Protein Atlas (HPA) RNA-seq tissue dataset, the FANTOM5 project, and the Genotype-Tissue Expression (GTEx) project, which are all summarized in the Human Protein Atlas (Tissue expression TFE3) provided concordant data. For example, a particularly strong TFE3 positivity was found by MSVA-403R in the lung and in seminal vesicles, two organs with particularly high rates of TFE3 RNA expression

Comparison of antibodies: True expression of TFE3 in all cell types found to be TFE3 positive by MSVA-403R is corroborated by identical stainings obtained by another commercially available independent antibody (termed “validation antibody”).

 

 

 

 

 

Normal tissue gallery