Study highlights processing effects on canine marrow IHC

CURRENT FULL VERSION: A new study in Veterinary Pathology examines a technical question with direct diagnostic consequences: how fixation and demineralization methods influence immunohistochemical assessment of canine bone marrow. According to the study abstract provided in the source material, the team collected sternal bone marrow from dogs with spontaneous disease within 24 hours of death, fixed samples in acetic acid-zinc-formalin or 10% neutral-buffered formalin for 24 hours, and then decalcified them with formic acid, hydrochloric acid, or EDTA before performing IHC. The work comes from Gabriella M. L. Diamantino, Janet Beeler-Marfisi, and Robert A. Foster, and extends a broader research program on how pre-analytic handling changes what pathologists can reliably see in canine marrow specimens. (escholarship.org)

That question matters because bone marrow cores are unusually vulnerable to processing artifacts. Unlike soft tissue biopsies, marrow samples often include mineralized bone that must be decalcified before sectioning. Veterinary diagnostic lab guidance notes that decalcification typically adds at least an extra day to processing for bone-containing samples, and if the lesion of interest is in bone rather than soft tissue, no preliminary report may be issued until that step is complete. (cvm.msu.edu)

The same research group already reported, in a 2024 Veterinary Pathology paper, that fixation and demineralization significantly affected histomorphology and DNA amplification in canine bone marrow. That earlier study used replicate sternal marrow samples and found that EDTA best preserved DNA amplification, while hydrochloric acid and formic acid caused greater damage, especially as demineralization time increased. The authors concluded that EDTA was the preferred demineralizer when molecular testing matters, although it required longer processing. (escholarship.org)

That molecular-preservation theme is consistent with findings from other mineralized tissues. In a recent Animals study, researchers developed a simple, fast, low-cost DNA extraction protocol for deer antlers and prepared trophy skulls that avoided commercial kits and cryogenic grinding. Their workflow used bead-based mechanical homogenization, a 4-hour enzymatic digestion in EDTA buffer with N-lauryl sarcosine and Proteinase K, followed by phenol-chloroform-isoamyl alcohol purification and centrifugal filtration. Tested across 60 samples—30 antlers and 30 pedicle samples from roe deer, fallow deer, and red deer—the method produced DNA suitable for multiplex PCR, with complete microsatellite genotypes obtained from all 60 samples. While that is a different use case from canine marrow histopathology, it reinforces the broader point that mineralized specimens can remain highly informative for downstream molecular analysis when gentler, well-matched processing methods are used.

Conference material from the American College of Veterinary Pathologists appears to preview the immunohistochemistry-focused companion study. In that abstract, the authors reported that EDTA decalcification yielded the best IHC results overall, whereas hydrochloric acid performed worst, with formic acid in between. That pattern aligns with broader pathology literature outside veterinary medicine, where EDTA is generally favored for preserving antigenicity and nucleic acids, while strong acids such as hydrochloric acid are faster but more likely to degrade proteins and weaken stain performance. (acvp.org)

There doesn’t appear to be a standalone press release or extensive public industry commentary on this canine study, but the findings fit with an established expert consensus on bone sample handling. Reviews and pathology guidance consistently describe fixation as an irreversible pre-analytic step, and they warn that decalcification can impair IHC and molecular assays if protocols are too harsh. A recent human bone marrow methods paper similarly emphasized that optimized fixation and decalcification protocols are essential because damage introduced at this stage can’t be corrected later in processing. (sciencedirect.com)

Why it matters: For veterinary professionals, this is less about a new biomarker than about the reliability of the diagnostic pipeline itself. When marrow IHC is used to classify hematopoietic neoplasia, confirm lineage, or support difficult inflammatory and infiltrative diagnoses, a false-negative or weak stain caused by processing can change interpretation. That’s especially relevant for referral hospitals and diagnostic labs handling suspected lymphoma, leukemia, plasma cell disease, marrow metastasis, or histiocytic disorders, where immunophenotyping may influence prognosis, treatment planning, and communication with pet parents. (pubmed.ncbi.nlm.nih.gov)

The operational tension is familiar: EDTA is gentler, but slower; acid decalcifiers are faster, but may sacrifice antigen preservation. For labs under turnaround pressure, that tradeoff is real. Still, this study strengthens the case that if marrow IHC quality is a priority, protocol standardization deserves attention, and labs may need to separate “fast morphology” workflows from “IHC- and molecular-ready” workflows rather than expecting one decalcification method to do both equally well. That last point is an inference based on the study pattern and broader pathology literature, not a direct recommendation from the authors. The deer antler DNA study points in the same practical direction: even heavily mineralized or processed specimens can yield high-quality downstream results when protocols are designed around preservation rather than speed alone. (nature.com)

What to watch: The next step is whether the immunohistochemistry-focused paper is fully indexed and whether veterinary diagnostic laboratories adopt or validate EDTA-heavy protocols for canine marrow, balancing better stain fidelity against slower turnaround and workflow demands. More broadly, it will be worth watching whether veterinary labs continue moving toward specimen-specific workflows that preserve both morphology and molecular utility in bone and other mineralized tissues. (acvp.org)