Message from the Director

Human tumor cells that can grow indefinitely in culture media are referred to as cancer “cell lines,” but the efficacy of anticancer drugs in cell lines is thought to be only 5-10% consistent with their efficacy when administered to actual cancer patients. In contrast, a patient-derived xenograft (PDX) is a model in which a portion of human tumor tissue is transplanted into immunodeficient mice and that tissue is capable of growing for a very long period. A PDX model retains the diversity of a tumor, so some studies have reported that when the efficacy of an anticancer drug is verified in a PDX model, the clinical efficacy of that drug can be predicted with 80% accuracy. Therefore, if PDX models with various types of cancers were prepared on a large scale, then the development of anticancer drugs could be accelerated. Moreover, PDX models are extremely vital to the advancement of cancer research. As an example, analyzing rare tumors such as sarcomas using human specimens at a single facility is difficult due to the small number of patients. However, tumors can be maintained in PDX mice for very long periods of time, so creating a PDX model allows for long-term analysis of patient samples.

In August 2018, the National Cancer Center started the “J-PDX Library” project to establish such PDX models with numerous cancers of many types on a large scale. As a result of collaboration between the National Cancer Center Research Institute and the National Cancer Center Hospital and National Cancer Center Hospital East, 555 types of PDX mice models were successfully engrafted as of December 2022, making the J-PDX Library one of the world’s largest PDX libraries. Moreover, medical facilities outside the National Cancer Center are currently collaborating to expand PDX models in a variety of cancer types. In addition to the significance of creating PDX models of Japanese origin, the J-PDX Library has the globally rare feature of including PDX models created from biopsy samples and PDX models of recurrence or drug resistance.

The National Cancer Center hopes that the J-PDX Library will be widely used by academia and industry to accelerate the development of new anticancer drugs and biomarkers in Japan.

Many of you who are viewing this webpage may have family members, relatives, or friends who have been diagnosed with cancer. Or you may have happened upon this webpage among many other pieces of information. Cancer treatment has been provided to patients as medical care based on trial and error and clinical research that has been conducted over several years, decades, or even centuries. The best and most recommended treatment, which has been verified in large-scale clinical trials and which has been found to be safe and effective, is indicated in guidelines as “standard treatment.” Nevertheless, some cancer patients do not respond to standard treatment or the treatment is temporarily effective but later ceases to be (development of resistance to treatment). The J-PDX Library is an important platform for the research and development of future cancer treatments. We thank you for your interest.

The J-PDX Library is a platform to test the efficacy of anticancer drugs by transplanting cancer tissue from patients into laboratory animals to mimic the state of the cancer in the patient’s body as much as possible and to verify the effects of anticancer drugs. Such a tumor-bearing animal model is called a patient-derived xenograft (PDX) model. With the cooperation of many cancer patients, we seek to construct a PDX library including every type of cancer. Moreover, the efficacy of anticancer drugs varies greatly among individuals, so we are collecting information on the sex, type of cancer, stage, genetic mutations, clinical information, and treatment history of each cancer patient who participates in research.

The PDX models created with your cooperation will be strictly managed by the National Cancer Center as if they were a representation of you, along with genetic and clinical information. We would like to use these representations (PDX models) of your cancer tissue for future research and development of cancer treatments. The PDX models registered in the J-PDX Library will be used not only by the National Cancer Center but also by researchers from research institutes around the world and pharmaceutical companies. We strictly screen the purposes of their research.

I have described the purpose of the J-PDX Library. Utilization of PDX models should dramatically advance cancer research, and the J-PDX Library should serve as a bridge between basic research and clinical research. The symbol of the J-PDX Library is intended to evoke the image of a bridge between basic research and clinical research in Japan. There are many types of cancers for which standard treatments have yet to be established and for which anticancer drugs have yet to be fully developed. The utilization of PDX models to elucidate the mechanisms of cancer development, to search for anticancer drugs that are efficacious, and to elucidate mechanisms of resistance to anticancer drugs will increase the probability of successfully developing anticancer drugs and make that process more efficient, and as a result, it should enable drugs from Japan to be provided to future cancer patients.