TUSTIN, Calif. (

TheStreet

) -- Regulators at the NYSE Amex have accused

Radient Pharmaceuticals

(RPC)

of allegedly misleading investors and the exchange about the company's relationship with the Mayo Clinic, the company admitted Tuesday.

Radient has claimed in public statements that it was working with the Mayo Clinic on a clinical validation study of the company's cancer-screening test Onko-Sure. Those statements led investors to believe that the prestigious research hospital was an active partner with Radient on Onko-Sure's development. However, as reported first by

TheStreet,

,

Mayo Clinic denied working with Radient on the Onko-Sure clinical trial

, explaining that the hospital only sold blood samples to Radient for use in the Onko-Sure study.

Radient claims it has been truthful in reporting the nature of the company's relationship with the Mayo Clinic, according to statements issued in response to

TheStreet's

story.

NYSE Amex halted trading in Radient's stock for more than 24 hours following publication of

TheStreet's

story on March 7. Nine days later, on March 16, regulators at the NYSE Amex sent Radient a notice informing the company of its failure to comply with the exchange's disclosure requirements for "allegedly omitting material information" in a written submission to the exchange, according to an 8-K filed by Radient on Tuesday with the

Securities and Exchange Commission

.

In its 8-K filing, Radient admits that NYSE Amex regulators specifically accuse the company of allegedly misleading investors about the company's relationship with the Mayo Clinic. Radient omitted any mention of the Mayo Clinic in a press release issued Tuesday regarding the NYSE Amex matter, referring instead to a "collaboration with a third party not-for-profit group practice."

The new accusations leveled against Radient by regulators at the NYSE Amex add to the company's troubles. Radient is already facing delisting from the Amex for failing to meet the exchange's listing standards. Radient is trying to appeal the delisting notice. Tuesday, Radient said a previously scheduled appeal hearing was postponed and is being rescheduled.

In addition to its troubles with NYSE Amex, Radient is facing a class-action lawsuit accusing the company of misrepresenting its dealing with the Mayo Clinic over the Onko-Sure test. Radient hired the law firm DLA Piper to represent the company in the class-action lawsuit.

Radient shares were down 8% to 40 cents a share in early Tuesday trading.

--Written by Adam Feuerstein in Boston.

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Adam Feuerstein writes regularly for TheStreet.com. In keeping with TSC's editorial policy, he doesn't own or short individual stocks, although he owns stock in TheStreet.com. He also doesn't invest in hedge funds or other private investment partnerships. Feuerstein appreciates your feedback;

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