Yes, the original epic rules found in the DMG...
...and the expanded epic rules found in the Epic Level Handbook both support the progression of full 10 level prestige classes into epic levels.
The original epic rules, however, give no examples of how to progress prestige classes, only guidelines.
For example, in the original epic rules, it only mentions that prestige class features that user character level as part of a formula to calculate a save DC progress at half character level after 20th, (the example used is the assassin death attack) and that class features that progress in a steady pattern also continue to progress (rogue sneak attack or barbarian rage) , but not ones that come to a stop before 20 (monk's damage) , or ones that are granted once (fast movement).
The DMG guidance listed may result in different effects when applied to prestige classes. For example, the Mystic Theurge will continue to gain both divine and arcane level boosts every level according to the DMG epic rules, which are primary source, as opposed to the SRD rules.