My dog has just started limping and whining?

[GraceWishart]

My Bernese mountain dog is about 5 years old (we're not entirely sure as she was a rescue) but a few months ago she was diagnosed with a malignant cancer on her lip.
She still is not showing any signs of health deterioration from this cancer, however today in the space of about 10mins she developed a limp. She also whines occassionally, but when I tried to examine her legs she didn't flinch or whine at all, but if she sits herself down or lies down she whines. We are worrying about what's wrong! Yesterday she also whimpered when I tickled her ears, but we have no idea if this is related to her wimp.
She also sat herself alone in the corner of a seperate room from my family and out other Bernese, jut quietly leaning against the window.

Does anyone know if this sudden limp/whimpering could be serious? We are taking her to a vet tomorrow.

 

[Lorraine]

I am so sorry.... 5 yrs is so young for this lovely dog to have a cancer.

Unfortunately all our large breeds are prone to bone cancers and I wouldn't rule out that this is the case. You don't say if it is front or back leg anyway and obviously it could be other things. I don't like however that she put herself alone in the corner separate to everyone.

Do so hope it isn't bad news and will keep all fingers crossed for you.

I love Bernese dogs, they are such gentle giants.