Coming off his best win as a pro, ex-Olympian Giovanni Lorenzo will be returning to his Dominican roots on April 4, 2005 when he fights for his country's middleweight championship at the Coliseo Poli Deportivo de San Cristobal.  Lorenzo, who knocked out previously unbeaten Dennis Sharpe in one round his last time out, will be facing Filaberto Alvarez, but the importance of this bout transcends the opponent.  Rich Ryan, who co-manages Lorenzo along with attorney Kurt Emhoff, says the boxer will donate his entire purse from next week's fight to help his childhood trainer, Salvatore Perez, who is battling cancer.  Perez started training Lorenzo at age 11 and helped him to the second round of the 2000 Olympics. "Sal is responsible for encouraging Gio to leave his homeland for the bigger opportunities U.S. boxing had to offer," said Ryan. Lorenzo himself credits Perez for turning his life around. "When I was a kid, I was heading for disaster, fighting in the streets almost daily, running with the wrong crowd. Many of my street friends are now dead," Lorenzo said.  "But Perez said to me, 'you think you're tough, let's see what you can do in the ring' and he showed me that I wasn't as tough as I thought"  Lorenzo, now based in the New York area, works with trainer Pastor Ralph Farrait, who also has generously pledged his 10% cut to help Perez. "This man is sick and I want to help, God bless him and I'll keep him in my prayers," Farrait stated. Local promoter Robert Faxas has organized the show, which will feature another New York based Dominican, Darling Jimenez.