Subcutaneous Tumor Models

Subcutaneous tumor models are an efficient and cost-effective choice for the determination of the response of tumors to a new drug. These models are used extensively in the scientific community, and a rich amount of historical data is available for the characterization of these models and comparison of tumor responses to other drugs.

Implantation into the flank of mice is minimally invasive and does not require anesthesia. Tumor growth is monitored during the study via calipering of the tumor dimension showing under the skin. However, subcutaneous tumor models grow under the skin usually forming spheric structures with limited interaction with the surrounding stroma.

  • Tumor models for fast and economic efficacy testing
  • Workhorse models for testing a variety of drugs in the lead optimization phase
Xenograft Study Example

Goal: The standard of care drug VX-680 was tested for it's potential to inhibit primary tumor growth of the human xenograft subcutaneous tumor model Molm-13.

Study layout: Molm-13 cells were implanted into the left flank of NMRI nu/nu mice, at 10 mice per group. After randomization on day 7, treatment was initiated on the same day. Test compound VX-680 was administered intraperitoneally at 50.0 mg/kg daily. Tumor growth was monitored by calipering twice per week, animal weight was measured three times per week, animal behavior was observed daily. On day 21, animals were euthanized and endpoint measurements for the determination of primary tumor volumes, and wet weights were performed.

animal weight of molm-13 tumor model

Animal weight of the Molm-13 subcutaneous xenograft tumor model is shown with vehicle and VX680 treatment.

molm-13 tumor growth after treatment with VX680 for compound testing

Monitoring of Molm-13 tumor growth was performed twice per week via caliper measurement. Shown are the mean values of tumor volume for vehicle and VX680 treatment.

Molm-13 tumor model testing with single dot graph

At day 22, tumors were isolated from the mice at necropsy and measured via caliper. Blotted are the mean tumor volumes in the top graph and the individual tumor volumes in the lower graph together with their median values and interquartile ranges. P values were calculated compared to the vehicle control using the unpaired t‑test and the one-way ANOVA with Dunnett´s test.

Syngeneic Study Example

While we have largely improved the outcome of syngeneic models using the subQperior™ engraftment route, we are still offering two syngeneic models (B16F10 and CT26wt) as routine subcutaneous models with an acceptable degree of ulcerations.

Please see a comparison of subcutaneous and subQperiorTM tumor growth of the B16-F10 tumor model below.

drug testing example with syngeneic tumor models on mice

B16-F10 tumor cells were implanted either into the left flank (subcutaneous, left side of the image) or into the mammary fat pad (subQperior, right side of the image) into C57BL/6 mice. Tumor growth was monitored by calipering twice daily. The upper images show the tumor growth of B16-F10 and the lower graphic shows the Kaplan-Meier survial curves with cause of death for every mouse.

Study Layout

Standard study layout

Subcutaneous tumor models are monitored via calipering after tumor cells were implanted into the flank of the mice. When tumors reach the predetermined tumor volume, animals are randomized in treatment groups based on tumor size and treatment starts. The mice are monitored on a regular basis: tumor size is measured via calipering twice weekly, animal weights are taken three times per week and animal behavior is observed daily. Once per week, we update the customer with a graphical presentation of the study progress.


A comprehensive report will be prepared by a PhD-level medical writer. The report will be custom-tailored for each project with data that can be used for filing official documents. The report includes material, methods, raw data, animal health chart, and graphs plus statistical evaluation.

Selection of optional services:

  • Isolation of tumors at necropsy for determination of volume and wet weight
  • Preservation of tissue via fixation or snap-freezing
  • Histological or pathological analysis of tumor tissue and mouse body
  • Determination of expression of genes or proteins
  • Plasma sampling and bioanalysis of compound or metabolites
  • Quantification of cytokines and chemokines in blood or tissue via MESO QuickPlex SQ120 multiplex analysis
  • Flow cytometry analysis for immune cell profiling
Study Options

Standard Efficacy Studies: Determination of the therapeutic effect of a new drug in an animal is a very exciting phase in a drug discovery project. Before performing an efficacy study, choosing the right tumor model and selecting the right drug candidates for in vivo testing will be supported by in vivo screening with the In Vivo Hollow Fiber Model.

Proof-of-Concept Studies: New drug candidates need to be tested not only for efficacy but also for their mechanism of action in the animal. Exploratory proof of concept studies can be performed together with histological, pathological, or molecular investigations of the biological activity of the drug on the tumor tissue.

Pharmacokinetic Studies: Pharmacokinetic studies on tumor-bearing mice are helpful in determining the concentration of drugs not just in plasma but in the tissue of the tumors.

Pharmacodynamic Studies: Pharmacodynamic studies elucidate whether and how a drug acts on its target.

Dose-Response-Relationship: Determine suitable drug doses for efficacy testing.

Drug Combination Studies: Combinations of drugs can lead to synergistic effects and vastly increased tumor response.

Survival Studies: A survival study gives data in addition to the reduction of tumor growth – it shows the number of partial and complete responders. The setup is also useful for drugs with no homogeneous response. Studies with an outcome of a mix of non-responders and responders are hard to interpret with common statistical values due to the high standard variation of the results. Survival studies can give meaningful results for such ambivalent drug candidates.

Custom Model Development

We continuously increase our portfolio of tumor models and provide custom development of new tumor models.

Cell lines: We can develop new tumor models a. based on customer-provided cell lines, b. based on a cell line from our extensive database of almost 200 cell lines or c. purchase a cell line from a commercial vendor.

Two-step approach: In case no tumor-model related data are available, we will perform a two-step approach to develop a new tumor model. In the first step, we identify a suitable mouse strain for tumor growth and determine the optimal conditions for tumor cell implantation. In a second study, we will monitor the tumor growth after tumor cell implantation into 12 mice for the determination of the growth characteristics of the tumors. This two-step approach guarantees satisfactory study results for subsequent efficacy studies.

Standard of care (SOC) treatment: Most of our models were tested with a variety of standard of care treatment. Please let us know which positive control is the most suitable for your drug candidate, and we will be happy to provide historical data with SOC treatment options.


The animal facility of Reaction Biology is located in Freiburg, Germany.

Our facility is certified under ISO 9001:2015, which is an international standard that specifies requirements for the quality management system and demonstrates the ability to consistently provide products and services that meet customer and regulatory requirements. Reaction Biology is committed to continuously maintain and improve its quality management system as a key element for the achievement of the highest customer satisfaction. ISO 9001
Quality Assurance

Animal work

  • Routine health monitoring of sentinel animals (according to FELASA guidelines)
  • Standardized operation procedures are in place of every step and every model

Cell lines

  • Routine authentication of tumor cell lines by STR profiling
  • Mycoplasma testing of tumor cells by PCR just prior to implantation

Study support

  • Studies generally start (tumor implantation) 3 to 5 weeks after receipt of the order
  • Suggestions for study layout to get statistically relevant results
  • Weekly study update and personal contact with the study supervisor
  • Reports are written by medical writers on Ph.D. level

Ethical principles

  • Our animal work is conducted according to the 3R (Replacement, Reduction, and Refinement)
  • We are working closely with our animal care committee to ensure timely adaptions of our animal care licenses to custom-tailor our client’s project to ensure the most meaningful study outcome
Animal Welfare

Reaction Biology uses laboratory animals to help our customers to understand the fundamental mechanisms behind malignancies and to discover therapeutics to prevent and treat cancer. Data obtained from animal models is critical in predicting the clinical outcome for an oncology drug candidate in development.

Animal welfare is of the utmost importance to us. Animal-based research is highly regulated to ensure ethical and responsible treatment. The mice in our facility are specifically bred for research purposes, and they are cared for to the very high standards.

We are working under GV-SOLAS and ISO9001 regulations in regard to standards of animal welfare and code of practice.

We employ three veterinarians and appropriately trained staff to ensure animal welfare is maintained at the highest standards. Regulation officers inspect our unit regularly.

Browse our subcutaneous tumor models