The tropics heat up with great boxing action when WORLD CHAMPIONSHIP BOXING:  MIGUEL COTTO VS. GIANLUCA BRANCO is seen live from Ruben Rodriguez Coliseum in Bayamon, Puerto Rico on SATURDAY, MARCH 4 (10:00 p.m. ET/7:00 p.m. PT/9:00 p.m. CT).  The HBO Sports team of Jim Lampley, Larry Merchant and Emanuel Steward will be ringside for the event, which will be closed-captioned for the hearing-impaired and presented in Spanish on HBO Latino. In a junior welterweight face-off, undefeated Miguel Cotto (25-0, 21 KOs), from Bayamon, takes on top-ranked Gianluca Branco (36-1-1, 19 KOs), of Civitavecchia, Italy, in a scheduled 12-round bout.  Considered by many to be the biggest boxing sensation to emerge from Puerto Rico since Tito Trinidad, Cotto is taking the sport by storm.  His victory streak includes 2005 KO wins over DeMarcus Corley, Mohamad Abdulaev and Ricardo Torres.Branco, who suffered his only loss in a hard-fought 12-round battle against Arturo Gatti in 2004, is on a four-fight winning streak.  He looks to spoil Cotto’s perfect record. Starting off the telecast will be the replay of Shane Mosley’s 10th round TKO win over Fernando Vargas.  That 154-pound showdown was held Saturday, Feb. 25 at the Mandalay Bay Events Center.