Histopathology Services

Histopathology provides tissue-level assessment of what a treatment did, both where it was intended to act and where it was not. In an efficacy study it establishes tumor architecture, viable tumor fraction, necrosis, and treatment-induced change. In a safety study it is the definitive endpoint, since organ-level toxicity frequently appears histologically before it appears in body weight, clinical observation, or clinical chemistry.

Altogen Labs provides histopathology on tumor and non-target tissue from in vivo studies, including tissue processing, sectioning, staining, and microscopic evaluation. To discuss a tissue panel for a planned study, request a quote.

Tumor assessment

A tumor growth curve describes the outside of a mass. Histology describes what it contains. Two tumors of identical volume can differ entirely in viable tumor fraction, and a treatment that produces extensive necrosis without reducing measured volume has produced a real effect that caliper measurement alone would miss and might even record as failure.

Assessment covers tumor architecture and differentiation, viable versus necrotic fraction, mitotic activity, invasion at the tumor margin, and stromal composition. In orthotopic and metastatic models, histology is frequently the primary means of quantifying burden, since lesions below the imaging threshold are detectable microscopically.

Safety and non-target tissue

In toxicology and tolerability work, the tissue panel extends beyond the target organ. Findings in liver, kidney, spleen, bone marrow, gastrointestinal tract, and other organs establish whether an observed weight loss or clinical sign has an identifiable tissue correlate, and whether a change is treatment-related, incidental, or background for the strain and age of animal.

That last distinction matters more than it appears. Background lesions are common in laboratory rodents, and a finding present in treated animals is only meaningful relative to its incidence in concurrent controls. Control tissue is therefore examined with the same rigor as treated tissue rather than as a formality, and findings are graded against a defined severity scale rather than described narratively.

Applications

Histopathology supports efficacy studies, safety toxicology, IND-enabling programs, immuno-oncology work where tissue-level immune changes accompany the flow cytometric panel, and teratoma formation analysis, where identification of tissues representing all three germ layers is the endpoint itself.

Applied examples

Necrosis without volume change. A treated cohort shows no difference in tumor volume but substantially reduced viable tumor fraction on histology, identifying an effect that the growth curve alone recorded as inactive.

Tolerability correlate. Body weight loss observed in a high dose group is investigated across the organ panel, with gastrointestinal findings identifying the origin of the effect and informing the dose selected for the subsequent study.

Micrometastatic burden. Lungs from a metastasis study are step-sectioned and metastatic foci counted microscopically, detecting burden below the threshold of whole-animal imaging.

Processing standards and evaluation

Fixation, processing, embedding orientation, section thickness, and staining are controlled and recorded, since orientation alone determines whether an invasive margin is assessable. Tissue destined for histology is identified at necropsy and fixed promptly, with separate aliquots taken where the same organ must also support molecular endpoints, because fixed tissue cannot subsequently be used for most protein and nucleic acid work.

Findings are graded against a defined severity scale, with criteria stated in the report. Evaluation is performed blinded to treatment group where the endpoint is subjective, and representative images are provided alongside per-animal findings rather than group summaries alone. All procedures involving animals are conducted under active IACUC protocols, and GLP standards are applied where a study is formally designated as GLP.

Send tissue panel, study type, and endpoints of interest, or request a quote.