A fear of losing drives unbeaten featherweight champion Oscar Valdez to strive for more.

Valdez (22-0, 19 KOs), from Nogales, Mexico, will be making the second defense of his WBO featherweight title against NABO champion and No. 1 contender Miguel Marriaga (25-1, 21 KOs), from Arjona, Colombia; Ramirez (34-0, 24 KOs), from Mazatlan, Mexico, will be making his first defense of the WBO super middleweight title against Top-10 contender Max Bursak (33-4-1, 15 KOs), of Kiev, Ukraine; Magdaleno (24-0, 17 KOs) of Las Vegas, Nev., will be making the first defense of his WBO junior featherweight title against WBO Latino champion Adeilson Dos Santos (18-2, 14 KOs), of São Paulo, Brasil.

The six world championship warriors have a combined record of 156-7-1 for a winning percentage of 95% with a victory by knockout ratio of 71%.

The pay-per-view telecast will also feature the pro debut of U.S. Olympic silver medalist SHAKUR STEVENSON

Promoted by Top Rank®, in association with Tecate, All Star Boxing, Zapari Boxing Promotions and Antonio Leonard Productions, the world championship event will take place, Saturday, April 22, at StubHub Center in Carson, Calif. It will be produced and distributed live by Top Rank Pay-Per-View, beginning at 9:00 p.m. ET / 6:00 p.m. PT.