In June 2016, the National Institutes of Health gave a University of Pennsylvania (UPenn) research team the go-ahead to begin a human CRISPR trial.

On Monday, a UPenn spokesperson confirmed to NPR that the institution’s researchers have officially started using CRISPR on humans — marking a national first that could lead to a more widespread use of the technology in the future.

CRISPR is however, a new kind of genetic engineering that gives scientists the power to edit DNA much more easily than ever. Researchers think CRISPR could revolutionize how they prevent and treat many diseases. CRISPR could, for example, enable scientists to repair genetic defects or use genetically modified human cells as therapies.

The powerful gene-editing technique called CRISPR has been in the news a lot. And not all the news has been good: A Chinese scientist stunned the world last year when he announced he had used CRISPR to create genetically modified babies.

But scientists have long hoped CRISPR — a technology that allows scientists to make very precise modifications to DNA — could eventually help cure many diseases. And now scientists are taking tangible first steps to make that dream a reality.

For example, NPR has learned that a U.S. CRISPR study that had been approved for cancer at the University of Pennsylvania in Philadelphia has finally started. A university spokesman on Monday confirmed for the first time that two patients had been treated using CRISPR.

One patient had multiple myeloma, and one had sarcoma. Both had relapsed after undergoing standard treatment.

The revelation comes as several other human trials of CRISPR are starting or are set to start in the U.S., Canada and Europe to test CRISPR’s efficacy in treating various diseases.

“2019 is the year when the training wheels come off and the world gets to see what CRISPR can really do for the world in the most positive sense,” says Fyodor Urnov, a gene-editing scientist at the Altius Institute for Biomedical Sciences in Seattle and the University of California, Berkeley.

Here are highlights of the year ahead in CRISPR research, and answers to common questions about the technology.

However, the spokesperson told NPR that the UPenn team has thus far used CRISPR to treat two cancer patients, one with multiple myeloma and one with sarcoma. Both had relapsed after standard cancer treatments.

For the trial, the researchers removed immune system cells from the patients, used CRISPR to edit the cells to target tumors, and then returned the cells to the patients’ bodies.

“Findings from this research study will be shared at an appropriate time via medical meeting presentation or peer-reviewed publication,” a UPenn spokesperson told NPR.

This might be the first human CRISPR trial in the U.S., but numerous others are already in the works to see if the technology can effectively treat a variety of diseases and disorders.

As gene-editing scientist Fyodor Urnov told NPR, “2019 is the year when the training wheels come off and the world gets to see what CRISPR can really do for the world in the most positive sense.”

CRISPR is currently humanity’s most effective and efficient gene-editing tool, and the technology is no longer just limited to editing plants or laboratory animals. In November 2016, Chinese scientists actually tested CRISPR in a human, and now, a human CRISPR trial is about to begin in the United States.

In June 2016, an advisory board of the National Institutes of Health (NIH) gave doctors from the University of Pennsylvania Health System (Penn Medicine), led by Edward Stadtmauer, the initial approval needed to begin human CRISPR trials. According to a post in a directory of ongoing clinical tests, the team is now almost ready to begin their trial.

For this first-of-its-kind medical test in the U.S., Stadtmauer and his team plan to use CRISPR to edit human T cells, which play a central role in the immune system, to target tumors. As many as 18 patients suffering from three types of cancer — multiple myeloma, sarcoma, and melanoma — could be enrolled in the study.

For their human CRISPR trial, doctors plan to extract blood cells from the patients and then edit the cells outside the body, an approach called ex vivo gene therapy. The goal is to turn the T cells into better cancer fighters before reintroducing them into the patient’s blood stream.

Using CRISPR, the doctors will delete two specific genes from the T cells. One is a so-called “checkpoint” molecule (PD-1) that cancer cells exploit to halt immune system activity. The other is a receptor that T cells use to detect dangers, such as germs or sickly tissue. They’ll replace that receptor with an engineered one designed to direct T cells toward tumors.

The Parker Institute for Cancer Immunotherapy, a charity created by Napster founder Sean Parker, is helping finance the trial, which is expected to begin in January 2018 and end in January 2033, according to the clinical trial directory posting.

However, a Penn Medicine spokesperson told the MIT Technology Review that a start date hasn’t been confirmed: “We are in the final steps of preparing for the trial, but cannot provide a specific projected start date.”

Still, after at least two years of planning, the U.S.’s first human CRISPR trial appears almost ready to begin, and once it does, the nation will officially join China on the very short list of places testing CRISPR on humans. Europe is expected to follow soon, though, with a human CRISPR trial using an ex vivo approach slated to begin later in 2018 courtesy of biotech firm CRISPR Therapeutics.

The results of these human clinical trials are likely to have a huge impact on the future of gene editing. Ultimately, while CRISPR does wonders in agriculture and other fields, proving its ability to cure human diseases is arguably a much larger goal, and reaching it could forever change healthcare.