* Highest subscriber adds in internet business in six years
* Cable communications business' rev up 5.4 pct
* NBC Universal revenue misses, but profits boosts results
* Shares rise as much as 2.6 pct
(Adds details and background on internet, NBC business; updates shares)
July 22 (Reuters) - Comcast Corp reported a better-than-expected rise in quarterly profit, helped by the highest subscriber additions in its high-speed internet business for six years and improved profitability at its NBC Universal unit.
Shares of the largest U.S. cable operator rose as much as 2.6 percent in early trading.
Comcast, which is seeking U.S. regulatory approval for its $45.2 billion bid to acquire Time Warner Cable Inc, added 203,000 net customers in its high-speed internet business in the second quarter ended June 30.
That was higher than the 161,000 additions analysts were expecting, according to market research firm StreetAccount.
Comcast aims to make its X1 cable TV cum internet service available in areas such as New York and Los Angeles within a year of the Time Warner Cable deal closing, which would help it pick up subscribers in those cities.
Comcast has also been steadily building out its WiFi network and said last week that it aims to have 8 million hot spots by the end of the year, covering 19 of the 30 largest U.S. cities. Time Warner Cable has 34,000 hot spots.
If the merger is approved, the combined company would have a nationwide footprint that could potentially challenge the dominance of U.S. telecom giants Verizon Communications Inc and AT&T Inc - an idea that Comcast has floated while touting the deal's benefits.
NBC PROFITS BOOST
Comcast's cable business, which also houses the internet business, lost 144,000 net video subscribers in the quarter, more than the 123,000 analysts were expecting, according to StreetAccount.
However, the strong showing of the internet business and a growth in services revenue helped the cable communications business' revenue grow 5.4 percent to $11.03 billion.
Revenue at NBC Universal - the media and entertainment company which Comcast bought last year - inched up 0.3 percent to $6.02 billion, missing analysts' expectations of $6.19 billion, according to StreetAccount.
Still the business reported a 20 percent jump in operating cash flow and better-than-expected profitability due to its broadcast television and filmed entertainment units, analysts at JPMorgan, Jefferies and Brean Capital said.
Net income attributable to Comcast rose 15 percent to $1.99 billion, or 76 cents per share. Excluding items, it earned 75 cents per share, higher than the average analysts' estimate of 72 cents, according to Thomson Reuters I/B/E/S.
Total revenue rose 3.5 percent to $16.84 billion, but fell short of the average analysts' expectation of $16.95 billion.
Comcast's shares were up 1.6 percent at $54.71 in morning trading. The stock has gained 3.6 percent so far this year through Monday's close.
(Additional reporting by Liana Baker; Editing by Savio D'Souza)