Washington (CNN) Donald Trump Jr. took a shot at one of his father's 2020 competitors, Joe Biden, on Tuesday night, criticizing the former vice president for not doing more to cure cancer during his time in the federal government.

"'Well, if you elect me president, I'm going to cure cancer,'" Trump Jr. said, imitating Biden , at President Donald Trump's reelection launch in Orlando. "Wow. Why the hell didn't you do that over the last 50 years, Joe?"

Trump Jr. appeared to be referencing Biden's statement during a campaign stop in Iowa last week when he said, "If I'm elected president, you're going to see the single most important thing that changes America: We're going to cure cancer ."

Trump Jr., at Tuesday's rally , went on to criticize the media for not following up on Biden's claim.

"Why didn't one of them say, well Joe, how exactly are you gonna do that? And why didn't you do it in the last eight years as vice president? And the prior 40 years in government and the Senate? I mean, you know, I don't know, seems like a reasonable question to ask," he said.

Facts First: Biden's efforts toward cancer research didn't formally begin until 2016, well into his tenure as vice president. Additionally, many of the cancer efforts instituted because of Biden's work on the issue are still ongoing -- in the private sector and within the federal government.

Cancer research and finding a cure became a priority for Biden after his son, Beau, died of brain cancer in 2015. The following year, the Obama White House launched the Cancer Moonshot initiative, spearheaded by the vice president.

It isn't exactly clear how Biden will increase any efforts to cure cancer if he becomes president, but after leaving office in 2017, the Biden Cancer Initiative was created. According to the organization , their goal is to "develop and drive implementation of solutions to accelerate progress in cancer prevention, detection, diagnosis, research, and care, and to reduce disparities in cancer outcomes."

Biden and his spouse, Dr. Jill Biden, resigned as co-chairs of the organization following the former vice president's 2020 announcement.

Any correlating effect of Biden's efforts toward finding a cancer cure and cancer diagnoses/deaths is not yet clear. The latest finalized data available from the Centers for Disease Control on new cancers and cancer deaths ends in 2016 -- the year the Obama White House moonshot initiative started.