ACR LANDS WITHOUT CLRNC.

Narrative

FLYING INTO DEN WE WERE GIVEN APCH CLRNC ABOUT 90 DEGS FROM THE FINAL APCH COURSE AND TOLD TO CONTACT TWR AT THE OM BEING CAUTIOUS OF THE 757 (PRECEDING) WAKE TURB. NO OTHER ADVISORY WAS GIVEN. WHILE TURNING ON TO FINAL THE TCASII CALLED 'TFC.' BOTH CREWMEMBERS LOOKED FOR TFC; COULD SEE NOTHING. NEXT THE TCASII CALLED 'DSND; DSND NOW.' THE FO (FLYING) THEN BEGAN A DSCNT (900 FPM) WHILE I CONTINUED TO LOOK FOR THE TFC. SOMEWHERE NEAR THE OM THE TCASII CALLED 'TFC NO LONGER A FACTOR.' THIS WAS UNNERVING BECAUSE WE FINALLY GOT THE TFC IN SIGHT AT THIS TIME; WHO WAS APCHING ON THE ADJACENT PARALLEL RWY. THIS WAS THE FIRST TIME TCASII HAD ISSUED A COMMAND WHILE I WAS FLYING SO I WAS GOING THROUGH MY HEAD WHAT HAD HAPPENED TO LEARN FROM THIS. AT THE SAME TIME I WAS MAKING SURE THE FO GOT AND STAYED ABOVE THE 757'S FLT PATH. WE SAW THE 757 CLR THE RWY AND NO ONE ELSE ON THE RWY AND LANDED WITHOUT INCIDENT. WHEN WE WERE CLRING THE RWY I NOTICED THAT WE WERE STILL ON APCH FREQ AND HAD NOT RECEIVED A LNDG CLRNC.