Submit processed tissue block or tissue section mounted on a charged, unstained slide.
AHL - Immunohistochemistry
Days Set Up:
Mo - Fr
1 - 2 days
If requested, an interpretive report will be provided All IHC stains will include a positive control tissue
Collection/ Processing Details:
A monoclonal antibody that recognizes a specific tyrosine kinase receptor, formed by the t(2,5) translocation called anaplastic lymphoma kinase (ALK)
The t(2,5) translocation forms a truncated protein NPM-ALK or p80, which is found in many cases of Anaplastic Large Cell Lymphoma (nuclear, nucleolar, and cytoplasmic staining)
Rare cases of Anaplastic Large Cell Lymphoma associated with trans-locations involving 2 p23 but genes other than NPM also express this antibody (cytoplasmic restricted staining)
A new type of Large B Cell Lymphoma recently described can express the full length ALK protein (cytoplasmic staining)
ALK-1 does not label normal lymphoid tissue
Rare reactivity with CNS system to ALK has been detected on frozen sections
Most Anaplastic Large Cell Lymphomas show cytoplasmic, nuclear, and often nucleolar staining (80% of cases)
Rare cases of Anaplastic Large Cell Lymphoma without NPM protein expression show cytoplasmic staining only (since the ALK associated protein is not trans-located to the nucleus)
A recently described subset of Large B Cell Lymphomas (lack t(2,5) and CD 30) exhibit cytoplasmic staining and express the full length ALK protein
The majority of Anaplastic Large Cell Lymphoma are positive for ALK-1. The reported positively rate varies from <15% to >67%
ALK-1 also can be seen in a subset of Large B Cell Lymphomas (cytoplasmic only staining)
Hodgkin’s Disease does not react with ALK-1
Recent data suggests favorable prognostic significance associated with ALK expression (10 yr. Survival rate of 78.5% for ALK positive cases vs. 44.4% survival for ALK negative cases). ALK expression also correlates with young patient age and low stage disease
ALK expression is also seen in most (60%) inflammatory myo-fibroblastic tumors
Benharroch D, et al. ALK-Positive Lymphomas, a Single Disease with a Broad Spectrum of Morphology. Blood, Vol. 91, No. 6, 2076-2084, 1998.
Pittaluga S, et al. The Monoclonal Antibody ALK-1, Identifies a Distinct Morphological Subytpe of Anaplastic Large Cell Lymphoma Associated with 2p23/ALK Rearrangements. Am J Path 151: 343-351, 1997.
Delsol G, et al. A New Subtype of Large B Cell Lymphoma Expressing the ALK Kinase and lacking the 2;5 Translocation. Blood, Vol. 89, No. 5, 1483-1490, 1997.
Pulford K, et al. Detection of Anaplastic Lymphoma Kinase (ALK) and Nucleolar Protein Nucleophosmin (NPM) – ALK Proteins in Normal and Neoplastic Cells. The Monoclonal Antibody ALK-1. Blood, Vol. 89, No. 4, 1394-1404, 1997.
Chan, John: Anaplastic Large Cell Lymphoma: Redefining its Morphologic Spectrum and Importance of Recognition of the ALK-Positive Subset. Blood, Vol. 91, 2076-84, 1998.
Cook, JR et al. Anaplastic Lymphoma Kinase (ALK) expressions in the inflammatory Myo-fibroblastic tumor; a comparative Immunohistochemical study. Am J Surg Pathol 25(11): 1364-1371, 2001.