This work was supported by grant 1R01CA152303-01.

Ethics Statement: Patient-derived colorectal adenocarcinoma tumor specimens were obtained from consenting patients at the University of Colorado Hospital in accordance with a protocol approved by the Colorado Multiple Institutional Review Board (08-0439). All animal work was performed under animal protocols approved by the University of Colorado Denver Institutional Animal Care and Use Committee (IACUC, Protocol # 51412(06)1E and 96813(04)1E).
1. Receiving and Preparing Patient Blood
<ol>
	<...

<ol>
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H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Notch/gamma-secretase+inhibition+turns+proliferative+cells+in+intestinal+crypts+and+adenomas+into+goblet+cells.">Notch/gamma-secretase inhibition turns proliferative cells in intestinal crypts and adenomas into goblet cells.</a> Nature. 435 (7044), 959-963 (2005).</li><li>Cassidy, J. W., Caldas, C., Bruna, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Maintaining+Tumor+Heterogeneity+in+Patient-Derived+Tumor+Xenografts.">Maintaining Tumor Heterogeneity in Patient-Derived Tumor Xenografts.</a> Cancer Res. 75 (15), 2963-2968 (2015).</li><li>Jin, K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Patient-derived+human+tumour+tissue+xenografts+in+immunodeficient+mice:+a+systematic+review.">Patient-derived human tumour tissue xenografts in immunodeficient mice: a systematic review.</a> Clin Transl Oncol. 12 (7), 473-480 (2010).</li><li>Julien, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Characterization+of+a+large+panel+of+patient-derived+tumor+xenografts+representing+the+clinical+heterogeneity+of+human+colorectal+cancer.">Characterization of a large panel of patient-derived tumor xenografts representing the clinical heterogeneity of human colorectal cancer.</a> Clin Cancer Res. 18 (19), 5314-5328 (2012).</li><li>Siolas, D., Hannon, G. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Patient-derived+tumor+xenografts:+transforming+clinical+samples+into+mouse+models.">Patient-derived tumor xenografts: transforming clinical samples into mouse models.</a> Cancer Res. 73 (17), 5315-5319 (2013).</li><li>Tentler, J. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Patient-derived+tumour+xenografts+as+models+for+oncology+drug+development.">Patient-derived tumour xenografts as models for oncology drug development.</a> Nat Rev Clin Oncol. 9 (6), 338-350 (2012).</li><li>Carson, F. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Histotechnology: A Self-Assessment Workbook. , (1996).</li><li>Arcaroli, J. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Common+PIK3CA+mutants+and+a+novel+3'+UTR+mutation+are+associated+with+increased+sensitivity+to+saracatinib.">Common PIK3CA mutants and a novel 3' UTR mutation are associated with increased sensitivity to saracatinib.</a> Clin Cancer Res. 18 (9), 2704-2714 (2012).</li><li>Arcaroli, J. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+NOTCH1+gene+copy+number+gain+is+a+prognostic+indicator+of+worse+survival+and+a+predictive+biomarker+to+a+Notch1+targeting+antibody+in+colorectal+cancer.">A NOTCH1 gene copy number gain is a prognostic indicator of worse survival and a predictive biomarker to a Notch1 targeting antibody in colorectal cancer.</a> Int J Cancer. 138 (1), 195-205 (2016).</li><li>Arcaroli, J. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Gene+array+and+fluorescence+in+situ+hybridization+biomarkers+of+activity+of+saracatinib+(AZD0530),+a+Src+inhibitor,+in+a+preclinical+model+of+colorectal+cancer.">Gene array and fluorescence in situ hybridization biomarkers of activity of saracatinib (AZD0530), a Src inhibitor, in a preclinical model of colorectal cancer.</a> Clin Cancer Res. 16 (16), 4165-4177 (2010).</li><li>Lieu, C. H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Antitumor+activity+of+a+potent+MEK+inhibitor,+TAK-733,+against+colorectal+cancer+cell+lines+and+patient+derived+xenografts.">Antitumor activity of a potent MEK inhibitor, TAK-733, against colorectal cancer cell lines and patient derived xenografts.</a> Oncotarget. 6 (33), 34561-34572 (2015).</li><li>Pitts, T. 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K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Potent+antitumor+activity+of+cabozantinib,+a+c-MET+and+VEGFR2+inhibitor,+in+a+colorectal+cancer+patient-derived+tumor+explant+model.">Potent antitumor activity of cabozantinib, a c-MET and VEGFR2 inhibitor, in a colorectal cancer patient-derived tumor explant model.</a> Int J Cancer. 136 (8), 1967-1975 (2015).</li><li>Tentler, J. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Identification+of+predictive+markers+of+response+to+the+MEK1/2+inhibitor+selumetinib+(AZD6244)+in+K-ras-mutated+colorectal+cancer.">Identification of predictive markers of response to the MEK1/2 inhibitor selumetinib (AZD6244) in K-ras-mutated colorectal cancer.</a> Mol Cancer Ther. 9 (12), 3351-3362 (2010).</li><li>Bardelli, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Amplification+of+the+MET+receptor+drives+resistance+to+anti-EGFR+therapies+in+colorectal+cancer.">Amplification of the MET receptor drives resistance to anti-EGFR therapies in colorectal cancer.</a> Cancer Discov. 3 (6), 658-673 (2013).</li><li>Bertotti, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+molecularly+annotated+platform+of+patient-derived+xenografts+("xenopatients")+identifies+HER2+as+an+effective+therapeutic+target+in+cetuximab-resistant+colorectal+cancer.">A molecularly annotated platform of patient-derived xenografts ("xenopatients") identifies HER2 as an effective therapeutic target in cetuximab-resistant colorectal cancer.</a> Cancer Discov. 1 (6), 508-523 (2011).</li><li>Davis, S. 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The authors have nothing to disclose.

The PDTX drug discovery platform offers an improved model to the shortcomings of other preclinical models that are unreliable in predicting clinical activity of novel compounds. Importantly, tumors in this model are biologically stable, retain metastatic potential, and exhibit similar drug responsiveness from generation to generation. In this model, patient derived tumors are injected into athymic nude mice, passaged, and subsequently used in therapeutic evaluation. There are several critical steps for a successful PDTX ...

Colorectal cancer (CRC) is a significant contributor to cancer deaths in the United States. In 2015, there were an estimated 132,700 new cases of CRC with 49,700 deaths 1. Although the prognosis in patients with localized disease is excellent, patients with advanced disease have poor outcomes, making this a major priority in the development of novel therapies. Despite standard of care chemotherapeutic regimens and newer biologics that are deployed against this disease, there has been only an incremental increase in overall survival. Accordingly, there is a significant effort in understanding the driver pathways involved in facilitating tumor growth in this disease. The Cancer Genome Atlas Network has recently identified numerous main pathways that are implicated in CRC dysregulation and include: WNT, phosphoinositide 3-kinase (PI3K), RAS, transforming growth factor-&#946; (TGF- &#946;) and TP53 2. Together, with investigations describing other pathways that potentiate growth in CRC have ignited the development of newer therapies aimed at significantly improving the survival in this patient population 3-5. Utilizing preclinical models in oncology drug development have been essential in this process in predicting the clinical activity of these novel compounds.
Various preclinical models have been utilized in the drug development process. Considering that preclinical transgenic animal models and immortalized cell lines have been unsuccessful in determining the clinical activity of novel oncology therapies, largely due to their inability to reflect the complexity of human tumors, patient-derived tumor xenograft (PDTX) models have been established. The greatest advantage of this model is that tumor heterogeneity remains intact and closely reflects the molecular characteristics and clonality of the originating patient tumor 6-9. PDTX models provide an excellent in vivo preclinical platform to study novel agents, drug resistance pathways, combinational strategies, and cancer stem cell biology 10.
A general overview of the PDTX process is illustrated in Figure 1. It begins in the clinic, consenting patients to allow some of their excess tumor tissue to be used for this research. Next, at surgery, a piece of the tumor is grossed by a pathologist and put into media to be transported to research personnel. Immediately after this, a section of the tumor is cut into small pieces and transplanted into immunodeficient mice subcutaneously. Once the tumor grows, it is passaged into different generations of mice in order to maintain the tumor10. Typically, after the F3 generation the tumor can be expanded into a treatment study where novel compounds and/or combinational therapies are evaluated. Utilizing Next Gen Seq (Exome Seq, RNA Seq and SNP array) potential predictive biomarkers are discovered that assist in the selection of patients that may derive benefit from a particular treatment.
The overarching goals of using PDTX models are to: 1) evaluate the efficacy of novel therapies as single agent or in combination and 2) identify predictive biomarkers of sensitivity or resistance prior to clinical investigation. In this manuscript, we provide the methodology in the initiation and maintenance of a CRC PDTX bank and provide the advantages and limitations of this model in drug development discovery.
<img alt="Figure 1" src="/files/ftp_upload/54393/54393fig1.jpg" /> 
Figure 1. Overview of the CRC PDTX Model Protocol. A patient derived tumor is received from surgery and immediately injected into athymic nude mice subcutaneously. Once the tumor grows it is expanded into subsequent generations and eventually expanded for treatment studies. Treatment responses are assessed and predictive biomarkers are identified that may aid in patient selection. <a href="https://www.jove.com/files/ftp_upload/54393/54393fig1large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>

<table border="0" cellpadding="0" cellspacing="0" width="915">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">RPMI or DMEM</td>
			<td style="width:81px;">Corning</td>
			<td style="width:119px;">10-040-CV</td>
			<td style="width:499px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Penicillin-Streptomycin</td>
			<td style="width:81px;">Corning</td>
			<td style="width:119px;">30-002-CI</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Non-essential Amino Acids</td>
			<td style="width:81px;">Corning</td>
			<td style="width:119px;">25-025-CI</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Fetal Bovine Serum</td>
			<td style="width:81px;">Corning</td>
			<td style="width:119px;">35-010-CV</td>
			<td>Thaw in -4 &#176;C, then activate for 30 minutes at 60 &#176;C water bath</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">CPT blood tube</td>
			<td style="width:81px;">BD vacutainer</td>
			<td style="width:119px;">362761</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Microcentrifuge tube</td>
			<td style="width:81px;">Surelock</td>
			<td style="width:119px;">A-7002</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Phospate-Buffered Saline</td>
			<td style="width:81px;">Corning</td>
			<td style="width:119px;">21-040-CV</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Cyrogenic vials</td>
			<td style="width:81px;">Cyroking</td>
			<td style="width:119px;">C0732901</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Plastic tumor cutting dish</td>
			<td style="width:81px;">Trueline</td>
			<td style="width:119px;">TR4001</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Scissors</td>
			<td style="width:81px;">Roboz</td>
			<td style="width:119px;">RS-5881</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Forceps</td>
			<td style="width:81px;">Roboz</td>
			<td style="width:119px;">RS-5135</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Matrigel (gelatinous protein mixture)</td>
			<td style="width:81px;">Corning</td>
			<td style="width:119px;">354234</td>
			<td>Store at -20 or -80 &#176;C, then thaw on ice, do not leave at room temperature</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">10% Formalin cups</td>
			<td style="width:81px;">Protocol</td>
			<td style="width:119px;">032-059</td>
			<td></td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:216px;">Liquid Nitrogen Dewar Storage</td>
			<td style="width:81px;">Thermolyne</td>
			<td style="width:119px;">CY50900</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Portable liquid nitrogen dewar</td>
			<td style="width:81px;">Nalgene</td>
			<td style="width:119px;">4150-2000</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Dimethyl Sulfoxide</td>
			<td style="width:81px;">Fischer</td>
			<td style="width:119px;">67-68-5</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Freezing container: Mr Frosty</td>
			<td style="width:81px;">Nalgene</td>
			<td style="width:119px;">5100-0001</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Isopropyl Alcohol</td>
			<td style="width:81px;">Decon</td>
			<td style="width:119px;">64-17-5</td>
			<td></td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:216px;">Trocars</td>
			<td style="width:81px;">Innovative Research of America</td>
			<td style="width:119px;">MP-182</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Anesthesia machine</td>
			<td style="width:81px;">Patterson Veterinary</td>
			<td style="width:119px;">none</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Anesthesia box</td>
			<td style="width:81px;">Patterson Veterinary</td>
			<td style="width:119px;">none</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Isoflurane</td>
			<td style="width:81px;">Vet one</td>
			<td style="width:119px;">1038005</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">F-Air Canister</td>
			<td style="width:81px;">Bickford Omnicon</td>
			<td style="width:119px;">80120</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Meloxicam</td>
			<td style="width:81px;">Vet one</td>
			<td style="width:119px;">5182-90C</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Calipers</td>
			<td style="width:81px;">Fowler</td>
			<td style="width:119px;">54-100-167</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Weight scale</td>
			<td style="width:81px;">Ohaus</td>
			<td style="width:119px;">Scout Pro SP601</td>
			<td></td>
		</tr>
	</tbody>
</table>

development and maintenance of a preclinical patient derived tumor xenograft model for the investigation of novel anti-cancer therapies

Patient derived tumor xenograft (PDTX) models provide a necessary platform in facilitating anti-cancer drug development prior to human trials. Human tumor pieces are injected subcutaneously into athymic nude mice (immunocompromised, T cell deficient) to create a bank of tumors and subsequently are passaged into different generations of mice in order to maintain these tumors from patients. Importantly, cellular heterogeneity of the original tumor is closely emulated in this model, which provides a more clinically relevant model for evaluation of drug efficacy studies (single agent and combination), biomarker analysis, resistant pathways and cancer stem cell biology. Some limitations of the PDTX model include the replacement of the human stroma with mouse stroma after the first generation in mice, inability to investigate treatment effects on metastasis due to the subcutaneous injections of the tumors, and the lack of evaluation of immunotherapies due to the use of immunocompromised mice. However, even with these limitations, the PDTX model provides a powerful preclinical platform in the drug discovery process.

Similarities of Common Mutations in the CRC PDTX Models and the TCGA
We investigated whether the percentage of common mutations (KRAS, NRAS, BRAF, PIK3CA, APC, CTNNB1 and TP53) in the CRC PDTX bank were representative to the mutation frequency seen in the CRC patient population. As shown in Figure 2A (TCGA) and B (CRC PDTX bank), the frequency of mutations in these gene...

Watch this Scientific Journal Video about Development and Maintenance of a Preclinical Patient Derived Tumor Xenograft Model for the Investigation of Novel Anti-Cancer Therapies at JoVE.com

Development and Maintenance of a Preclinical Patient Derived Tumor Xenograft Model for the Investigation of Novel Anti-Cancer Therapies

Utilizing patient-derived tumors in a subcutaneous preclinical model is an excellent way to study the efficacy of novel therapies, predictive biomarker discovery, and drug resistant pathways. This model, in the drug development process, is essential in determining the fate of many novel anti-cancer therapies prior to clinical investigation.

Patient derived tumor xenograft (PDTX) models provide a necessary platform in facilitating anti-cancer drug development prior to human trials. Human tumor ...

The overall goal of this subcutaneous Patient Derived Tumor Xenograft procedure is to the study the efficacy of novel therapies predictive biomarker discovery and drug resistant pathways in tumors. This method can help answer key questions in the oncology field about whether a particular drug exhibits activity against a specific tumor type. The main advantage of this technique is that Patient Derived Tumor Xenographs maintain the molecular, genetic and histologist heterogeneity typical of the tumors of origin, making the model more clinically relevant.Demonstrating the procedure will be Stacey Bagby, a professional research assistant and certified veterinary technician from our laboratory. After collecting one to two milliliters of blood in a blood cell separation tube containing sodium citrate, centrifuge the samples and transfer the peripheral blood mononuclear cell layer into a 1.5 milliliter micro-centrifuge tube. Fill the tube to the top with sterile PBS.Then, spin down the cells again. Followed by a quick wash with one milliliter of PBS, being careful not to disturb the PMBC pellet. Then, use a pipette to transfer the plasma from the blood cell collection tube to a 1.5 milliliter sterile cryogenic vial, and store the plasma and the PBMC pellet at negative 80 degrees Celsius.Transfer the human tumor tissue to the animal facility in a sterile cup containing complete medium and place the cup in a laminar flow hood. As soon as possible, after harvesting, transfer the tissue into a sterile plastic cutting dish in a small amount of the retrieval medium. Then, using autoclave sterilized small scissors and forceps, cut the tissue into approximately three by three by three milliliter pieces and place 10 to 12 pieces into an autoclave sterilized 1.5 milliliter micro-centrifuge tube containing 300 microliters of gelatinous protein mixture solution on ice for the implantation.For flash frozen storage, transfer the appropriate number of tumor pieces into a new 1.5 milliliter micro-centrifuge tube and place the vial in a liquid nitrogen doer. Then, place in a minus 80 degrees Celsius freezer. For formal infixing and paraffin embedding, place three small tumor pieces into a 10 milliliter 10%formalin cup for 24 hours.After the tissues are processed into paraffin embedded blocks, transfer any remaining tissue pieces into a cryogenic tube. Then, add one milliliter of complete medium supplemented with 10%DMSO to the tissue and store the tubes on ice until they can be transferred into an isopropyl alcohol freezing container. And put that container in a minus 80 degrees Celsius freezer.To inject the tumor tissue, load the pieces of tumor stored in the gelatinous protein mixture solution into autoclaved 12-gauge trocars, taking care that each tumor piece is completely inserted into the trocar. Next, confirm a lack of response to toe pinch in a six to eight week old athymic, nude mouse and transfer the mouse onto a clean field in a sterile laminar flow hood. Deliver the F0 tumor subcutaneously to the dorsal neck region and to each side of the mouse's flank, followed by the subcutaneous administration of analgesia distal to one of the flank sites of tumor injection.Then, place the mouse back in its cage with monitoring until it is fully recovered. Monitor the growth and health of the xenograph-implanted mice at least once per week, recording the tumor sizes, tumor generation, date of tumor injection, and health of the mice in an appropriate tracking system. When a tumor reaches approximately 1, 500 to 2, 000 cubic millimeters in size, use autoclaved scissors and forceps to excise the tumor and passage the F1 tumor into the next generation of five animals, as just demonstrated, taking care to collect flash frozen formalin and viable tumor samples as demonstrated for each tumor.When the remaining mice from the F0 tumor group exhibit tumors approximately 1, 500 to 2, 000 cubic millimeters in size, collect these tumors as just demonstrated for collection. When the stage F15 tumor generation is reached, use the earliest generation of viable tumor pieces available in liquid nitrogen storage for the next series of tumor injections. When the desired tumor is very large, 1, 500 to 2, 000 cubic millimeters, follow the procedures above to collect the tumor to expand it into the desired amount of mice.Dose the mice with the drug and weigh and measure them twice per week. Randomize the mice into treatment groups with 10 tumors per group, and a group tumor volume average of 100 to 300 cubic millimeters within a few standard deviations of each other. Then, sort the mice into the appropriate groups for treatment.Dual color fluorescence in situ hybridization for the human and mouse caught one DNA demonstrates that the human stromal cells in the F0 tumor are replaced by the mouse stromal cells in the F1 tumor. Whereas, all of the human-derived hepatocyte growth factor in the F0 generation is replaced with mouse hepatocyte growth factor in F1 generation, the vascular endothelial growth factor ligand consists of both human and mouse protein in the F1 generation. The treatment of different generations of the same tumor does not change the treatment response.With the resistance or sensitivity of the tumor appearing to be tumor strain rather than tumor generation specific. Further, the frequency of mutations in these commonly mutated genes is very similar between the cancer genome atlas and the colorectal patient-derived tumor xenograph bank. Suggesting that the common mutations observed in the colorectal patient population are well represented in the colorectal patient-derived xenotransplant model.Once mastered, this technique can be completed in one to two hours, if performed properly. While attempting this procedure, it is important to have a cohesive clinical team for identifying and obtaining consent from the cancer patients and for the removal and grossing of the tumor tissue. Following this procedure, other methods, like the investigation of anti-cancer compounds as single or combination agents, can be performed to answer additional questions about the viability of these strategies for patients with a particular tumor type.After its development, this technique paved the way for researchers in the field of oncology to explore novel cancer therapeutics, tumor heterogeneity, treatment resistant mechanisms, cancer stem cell biology, and tumor stromal interactions. After watching this video, you should have a good understanding on how to develop and maintain a patient derived tumor xenograph model for evaluating novel cancer therapeutics.

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JoVE Journal

Cancer Research

13.4K Views.  University of Colorado Denver Anschutz Medical Campus. The overall goal of this subcutaneous Patient Derived Tumor Xenograft procedure is to the study the efficacy of novel therapies predictive biomarker discovery and drug resistant pathways in tumors. This method can help answer key questions in the oncology field about whether a particular drug exhibits activity against a specific tumor type. The main advantage of this technique is that Patient Derived Tumor Xenographs maintain the molecular, genetic and histologist heterogeneity typical of the...