I know that Google Translate is not the be-all-end-all, but perceiving a non-literal translation, I gave it a go. "These results are noteworthy" -- not presently accepted by DL -- seems to be a reasonable translation.
It's important, too, because there are meaningful differences between "These results are to be emphasized", which might imply that one should downplay other, perhaps valid, results, and "These results are noteworthy" which expresses either mild surprise or an affirmative statement that people should pay attention to these results, implying no intent to conceal or downplay other results.
I agree that "noteworthy" is reasonable in this context. We all should be aware that Google Translate is crowdsourced much like Duolingo. Therefore, you are likely to find a lot of useless information there left by sources who believe their instincts are just as good as another's university degree so one must have one's brain fully engaged when evaluating the outcome of GT's "translations". I think that your observation about stressing some results may downplay others is a natural consequence of souligner. In the same sense, a dress might highlight a person's features in such a way as to emphasize one area and draw attention away from another. http://www.larousse.com/en/dictionaries/french-english/souligner/72855
[Ouch! Down-voted by The Phantom. If I have said something wrong, please enlighten me. In the meantime, I stand by my comment.]
You raise a good point but I think the real issue is that the results are intentional.
The explosion of the volcano is noteworthy means that it is worth noticing that the volcano exploded.
The explosion of the volcano is to be emphasized means that someone should do something in some context in some way so that the explosion is noted. It is not just noteworthy. It has been made noteworthy or more noteworthy than it otherwise would have been.
Report. It sounds like it's a reasonable translation, just one they hadn't thought of. Now of course I suspect the literal meaning of soulinger is to underline 'sous + ligner' but that is something that was used a lot before the days of bolt or italic fonts to emphasise a word or phrase. Since highlighting is used for exactly the same purpose to make a word or phrase stand out, I think it is reasonable as a translation.
sont (are) à souligner (to be emphasised) It's the passive infinitive as willijanb has said and there is more about it here: http://french.about.com/od/grammar/a/passiveinf.htm It is passive here because there is no information on who is doing the emphasising of the results.