Former President Jimmy Carter, a poster child for immunotherapy cancer treatment, teaches during Sunday School class at Maranatha Baptist Church in Plains, Ga., last month after an MRI showing no cancer on his brain. This month, President Barack Obama announced that the U.S. is embarking on a "moonshot" to cure cancer. (AP Photo/Branden Camp)

Everyone knows and loves someone who has been stricken with cancer. Many have lost someone to cancer.

The same was once said of measles, polio and tuberculosis. And while cancer clearly is a much more complicated disease, there can be no excuse for not pursuing cancer's cure far more vigorously.

That's why President Obama's "moonshot" to cure cancer was such a welcome announcement earlier this month.

Of course, it is an Obama initiative — so certainly there already have been naysayers who call the effort naive, especially from those who don't understand the real aim or who were tripped up by the shorthand language of public communication to describe the "cure" as though it might be a preventive vaccine for people with genetic glitches.

That's not the case. This initiative is prefaced on the understanding that there will be no single cure because cancer isn't one disease but hundreds. This cure will build on scientists' newest understandings of how cancer forms and spreads. It will be honed by scientists who are developing new ways to thwart cancer by using the body's own defenses.

Just ask former President Jimmy Carter, whose advanced melanoma was put in check last year using immunotherapy to tap the body's immune system to attack and check his stage 4 cancer.

For most of us, chemotherapy is still the mainstay cancer treatment. But the first immunotherapies strip away some of the ways tumors hide, without as many side effects as chemo. These newest therapies have been successful in melanoma and lung cancer, and now they are being explored for a wide variety of tumors.

But to be clear, previous moonshots and cancer-cure programs have also had naysayers — and, in the case of cures, have often had less than stellar results.

The original moonshot, the top priority President Kennedy assigned to beating the U.S.S.R. to a manned landing on the moon, had a very notable opponent — Sen. J.W. Fulbright, then-chairman of the Committee on Foreign Relations. In a speech to the Senate in October of 1963, Fulbright "examined the manned-moon program on the test of its urgency as contrasted with national deficiencies in education and employment, and in adequate financial support for medical research into the cause of cancer and incurable arthritis," The New York Times reported at the time.

Well, we made it to the moon in 1969. And President Richard Nixon in 1971 announced a war on cancer, but we all know how that ended.

Now four decades later, researchers working with the Obama administration understand that cancer is not our grandmother's pneumonia, so thinking of this new moonshot as a single "cure" sells it far short.

"Moonshot medicine," more correctly dubbed precision medicine, is not predictive genetics. Nor is it one-size-fits-all medicine like the Salk polio vaccine. Instead its aim is to use the genetic makeup of a patient who already has a disease — like cancer — to try to understand the molecular causes behind it and then target the treatment, said Carlos S. Moreno to The New York Times last February. Moreno is an associate professor in the department of pathology and laboratory medicine at the Winship Cancer Institute of Emory University.

Last October, Vice President Joe Biden, in his speech to say he would not enter the race for president in 2016, electrified the nation by saying, "I believe we need a moonshot in this country to cure cancer. It's personal. But I know we can do this."

Though cancer death rates are dropping thanks to other breakthroughs, the big C remains the No. 2 killer of Americans. There were an estimated 589,430 cancer deaths in 2015.

Meanwhile, federal cancer funding has been flat for more than a decade except for a one-time $1.3 billion burst from President Obama's stimulus program early in his administration. The federal government spends more than $5 billion a year on cancer research. Biden already is credited with having helped push through Congress a budget package last month that, among other things, increased cancer funding by $260 million this year.

In January, the president committed to this moonshot historic cancer research push, and he chose Biden to lead the effort — officially dubbed the Cancer Moonshot 2020. The initiative will build on the $2 billion increase in funding approved for the National Institutes of Health last year, and the aim is to develop a vaccine-based immunotherapy to fight cancer by the end of the decade.

We must not mislead or oversimplify the odds and challenges facing scientists who study the many different forms of the disease. Nor can we discount the stubborn obstacle of bringing researchers to share their information. But even if all this effort does is bring better, less brutal and more affordable cancer treatments, we as a nation will be the better for it.

Hope springs eternal. And it's contagious. Let's be infected.