What does the Good News refer to? What is the Good News?

Is there a different meaning when Jesus mentions it and when Paul does?

Edit:

I'll clarify my question. Jesus mentions the Good News (or "gospel" in some translations) in Mark 1:15:


  And saying, The time is fulfilled, and the kingdom of God is at hand: repent ye, and believe the gospel. 


It seems that His gospel is that "the time is fulfilled, and the kingdom of God is at hand." Does that relate to the time of His laying down His life for the sin of men, as the term "gospel" is understood after His death, or does the term have another meaning in Jesus' mouth?
The "Good News" in the Bible refers specifically to the Gospel of salvation. Simply that.

As you stated, it is sometimes translated as "gospel". This is because, the Greek word it came from, can be translated as "good news", "glad tidings", or "gospel", etc.


  (from Koine Greek euangélion — also translated as "gospel", "glad tidings" and variants