The CADETSM HM assay: a powerful new approach for identification of canine histiocytic malignancy (HM)


The CADETSM HM ASSAY is a novel DNA-based approach that aids distinction between HM and other round cell neoplasms that share similar symptoms and histologic appearance.

Canine histiocytic malignancy – an overview

Histiocytic malignancy (HM) is a typically aggressive canine cancer that can arise in a wide variety of anatomical locations, often affecting multiple sites in abdominal organs and the skin. Several breeds are highly predisposed, notably the Bernese Mountain Dog and the Flat-Coated Retriever, in which HM contributes to up to 50% of all deaths1. Other commonly affected breeds include the Golden Retriever and the Rottweiler; however any breed may be affected.

Diagnosis of HM can be highly challenging, and is often achieved through sequential exclusion of other likely differentials. The prognosis for dogs diagnosed with HM is very poor, with typical mean survival of less than two months2. Unfortunately the rapid progression and lack of effective treatments means that many HM cases are euthanized within days of diagnosis3.

Why does HM confer a particular diagnostic challenge?

The symptoms of HM are shared by several other round cell neoplasms, both benign and malignant, which may also appear very similar at the cellular level, but which typically have more optimistic outcomes and therapeutic options4-6. Some examples are shown below.

Accurate distinction between these diseases is therefore critical, but is not readily achieved. Some studies have shown that as many as 70% of cases that are initially identified as HM may be misclassified7,8.

Distinction between HM and lymphoma can be particularly challenging. Our research suggests that as many as 20% of cases diagnosed as being consistent with HM using routine methods are subsequently reclassified as lymphoma when evaluated with more comprehensive techniques.

The traditional path to diagnosis of HM

Routine microscopic evaluation of suspected HM cases can be subjective and inconclusive. The use of special stains for specific cell types can be informative but is time-consuming, expensive and often impractical, since they are not all broadly effective in a routine clinical setting 9. This lengthy process can add greatly to the anxiety of the concerned owner, and may delay initiation of treatment for those cases where the ultimate diagnosis offers this option.

The CADETSM approach

The CADETSM HM Assay represents a powerful new, rapid and minimally invasive approach for distinction between HM and other similar diseases. Minute samples of representative tumor tissues are required. The assay determines the number of copies of a specific DNA sequence that are present in the tumor cells of suspected HM cases. A reduction in the number of copies present is consistent with a diagnosis of HM.

The assay has been validated on samples from over 500 unique, pathology verified canine cancer specimens from  HM and multiple other tumor types that can resemble HM, including lymphoma, hemangiosarcoma, amelanotic melanoma, mast cell tumor and plasmacytoma. The results demonstrate that this genetic signature is a highly sensitive and accurate marker for distinction between canine HM and these other tumor types, with sensitivity of 78% and specificity of 95%.

What are the key advantages offered by the CADETSM HM Assay?

  • The CADETSM HM Assay avoids the subjectivity associated with microscopic evaluation of tumor types that show similar cellular appearance.
  • The assay is not dependent on costly and invasive surgical biopsy or the use of special stains.
  • The assay has been validated on a variety of routine clinical sample types, including aspirated cells, cytology slides and formalin-fixed tissue.
  • No specialized sample collection materials are required, and the assay is readily implemented in a routine clinical setting.
  • Depending on the nature of the submitted sample, results are available in as little as two business days after receipt by the testing laboratory.

Please click the button below to review sample submission guidelines and to order the CADETSM HM ASSAY.


What are the implications of the CADETSM HM Assay for owners/breeders and their dogs?

Exclusion of HM as a diagnosis offers a more positive outlook and broader opportunities to consider treatment strategies. Conversely, where the diagnosis is consistent with HM, both owner and veterinarian are better informed to consider options that may include palliative care. Ultimately, by reducing misclassification of HM we as a community can better advance research into new treatment strategies that will improve the outlook for these cases, provide more accurate assessments of disease frequency and better identify individuals at risk of developing HM.

Click on the image to the right to view a printable flyer of information on the CADETSM HM Assay.

Literature cited

  1. Erich SA et al. (2013) doi: 10.1016/j.tvjl.2013.09.062
  2. Abadie J et al. (2009) doi: 10.1093/jhered/esp039
  3. Fulmer AK and Mauldin GE. (2007) PMCID: PMC1978291
  4. Richards KL and Suter SE. (2015) doi: 10.1111/imr.12238
  5. Finotello R et al. (2016) doi: 10.1111/vco.12193
  6. Faller M et al. (2016) doi: 10.1111/jsap.12531
  7. Pazdzior Czapula K et al. (2014) doi: 10.1007/s11259-014-9622-1
  8. Dervisis NG et al. (2016) doi: 10.1111/vco.12252)
  9. Kennedy K et al. (2016) doi: 10.3390/vetsci3010002