Update: Check out the addition of the Bar-Kays’ “Soul finger” (1967) and Queen “The Invisible Man” (1989):
Huey Lewis & The News vs. Ray Parker vs. The Bar-Kays vs. Queen

Steve commented on Huey Lewis & The News vs. Ray Parker Jr and brings to our attention  The Bar-Kays‘ 1967 track “Soul Finger”.

I took a listen and there is a definite similarity here. Even the kids singing “Soul Finger” reminds me of “Ghostbusters!”. Check out all three below.

Here’s some reading from Wikipedia:

I found this on wikipedia regarding the Huey Lewis & The News track “I Want a New Drug” (1984) and Ray Parker Jr.’s theme to the movie Ghostbusters (also 1984). Ever since this song, if  anyone asks me “who I’m gonna call” you know what I’m gonna say.

In 1984, Ray Parker Jr. was signed by the producers of Ghostbusters to develop the film’s title song. Later that year, Huey Lewis and the News sued Parker, citing the similarities between the “Ghostbusters” song and their earlier hit “I Want a New Drug”. According to Huey Lewis and the News, this was especially damaging to them since “Ghostbusters” was so popular, rising to number one on the charts for three weeks. Parker and Lewis later settled out of court. Huey Lewis has stated that his experiences with the producers of Ghostbusters may have been indirectly responsible for getting his band involved with the movie Back to the Future.

In the 2001 Behind the Music special, Huey Lewis stated: “The offensive part was not so much that Ray Parker Jr. had ripped this song off, it was kind of symbolic of an industry that wants something—they wanted our wave, and they wanted to buy it. … [I]t’s not for sale. … In the end, I suppose they were right. I suppose it was for sale, because, basically, they bought it.” As a result of this statement, Parker Jr. filed a suit against Lewis, claiming he violated the settlement’s confidentiality agreement and seeking an unspecified amount of compensatory and punitive damages as well as attorney fees.

An issue of Premiere Magazine would later feature an anniversary article about the movie Ghostbusters. In that article, the filmmakers admit to using the song “I Want A New Drug” as temporary background music in many scenes. They then said that they had made an offer to Huey Lewis and the News to write the main theme, but they declined. The filmmakers then provided Ray Parker Jr film footage—with the Huey Lewis song in the background—to aid Parker in writing the theme song.  – Huey Lewis & The News on Wikipedia