It’s certainly not easy to find millionaire-maker stocks if you only have $50,000 or less to invest. In order to turn that amount of money into $1 million using a single stock, you’ll need vision, a contrary nature, tenacity, and a great deal of patience.

The vision and the contrarian part are important, because you’ll need to spot the huge potential of a company that the Street is missing or not yet acting on. Addiitonally, you’ll have to be contrarian enough to invest a significant amount of your money in the stock anyway.

The tenacious part is necessary, as the ability to hold onto the stock or even buy more of it as it falls becomes even more important. That’s because investors and short sellers don’t see or don’t care about the company’s huge, long-term opportunities. And of course, you’ll have to have enough patience to hold onto the stock long enough to benefit from the fruits of the company’s victories.

Having said all that, here are three potential millionaire-maker stocks.

Exact Sciences (EXAS)

First on this list of millionaire-maker stocks is Exact Sciences (NASDAQ:EXAS), an exciting company in the world of cancer research. Exact Sciences has developed one highly successful cancer test, its Cologuard test for colon cancer. Additionally, the company is getting close to releasing a second test that looks poised to be many-times more lucrative for the company.

Specifically, EXAS has developed a blood test that “detected about 15 cancers in a… study comparing blood samples from cancer patients with samples from people presumed to be healthy,” The Wall Street Journal reported last October. It was able to detect 61% of the cancers and yielded correct, negative results 98% of the time. The latter figure is important because false positives will result in unnecessary invasive biopsies that are difficult both physically and emotionally for patients. They’re also very expensive for health insurers.

While multiple other companies have developed blood cancer tests, most are start-ups that won’t have as much money and personnel to develop and market their tests. The one exception is Grail, which was acquired by Illumina (NASDAQ:ILMN). However, it appears that, due to regulators’ qualms and Carl Icahn’s intervention, Illumina will have to spin off Grail.

In the longer-run, millions of people globally will want to take blood cancer tests annually, because doing so could easily save their lives. As a result, Exact Sciences’ top- and bottom-lines look poised to soar many, many times by 2030.

Eisai (ESAIY)

Eisai (OTC:ESAIY), a Japanese drug maker, has developed the first Alzheimer’s drug that seems to work.

The drug, Leqembi, “met its primary and secondary endpoints” in a Phase 3 trial, and the treatment has been shown to slow down the progression of the deadly disease, which slowly degrades sufferers’ quality of life.

Specifically, the drug produces a “consistent reduction of clinical decline” and delays the onset of the “moderate” stage of the disease by a year. Further, those who take the drug show meaningfully lower amounts of amyloid plaque in their brains than the patients who don’t receive it. In a Phase 3 trial, “the cognitive decline [of those who took the drug] was 27% slower over 18 months” than patients who did not receive it.

In January, the FDA agreed to accelerate the timeline for a potential approval of the drug, which is also being reviewed by the EU on an expedited basis. Since there are currently 6.5 million Alzheimer’s patients in the U.S. alone, and the nation’s Baby Boomers have entered the stage at which they can contract the disease, the drug should be extremely lucrative. The EU’s population is also rapidly aging.

Eisai has agreed to divide its profits from Leqembi equally with Biogen (NASDAQ:BIIB), which is going to manufacture the drug. But Eisai’s market capitalization is only $16.5 billion, versus Biogen’s $41.4 billion, making the Japanese company a much better way to play the drug’s growth.

Eisai’s trailing price-earnings ratio is just 20-times, which is very low, given the huge opportunity presented by Leqembi. As the drug gets closer to being approved in the U.S. and Europe, the stock should skyrocket.

iCAD (ICAD)

Rounding out this list of millionaire-maker stocks is iCAD (NASDAQ:ICAD), a smaller-cap company with significant upside potential. Currently, iCAD has a market capitalization of only $33.5 million. However, this innovative company has developed an AI-based product that detects breast cancer significantly more effectively than the standard tools.

Moreover, one of iCAD’s longtime customers is Solis Mammography, which reported that it “operates more than 100 centers in 13 major markets” as of last October.

Also noteworthy is that iCAD, which generated revenue of $27.9 million last year, recently launched a partnership with Alphabet’s (NASDAQ:GOOG) Google Health. Under the deal, Google Health’s AI will be incorporated into iCAD’s breat cancer detection products.

During the company’s fourth quarter earnings call, CEO Dana Brown notes that Google has “great brand awareness [and] great processing power,” along with a background in “data security and privacy.” As a result, the alliance should help iCAD sell its products more quickly.

I believe that Brown was downplaying the extent to which Google’s tremendous brand name, connections, and technological acumen will boost iCAD’s sales. Also, I still believe that Alphabet can use its tremendous financial resources to help iCAD market its tools, even though Brown said “Google would not [likely be] a channel partner from a sales perspective for us.”

Also importantly, Brown reported that, after iCAD sells its cancer therapy business, it expects to “be cash flow positive” and profitable overall “before the end of 2024.”

As of the date of publication, Larry Ramer owned shares of ICAD and EXAS. He may purchase shares of Eisai during the week of April 10. The opinions expressed in this article are those of the writer, subject to the InvestorPlace.com Publishing Guidelines.