PHOENIX - Arizona Senator John McCain has persevered through more in his life than most of us can imagine. Now, a new trial is challenging the senator and his family.

The tumor is known as Glioblastoma.

Doctors say it is connected to a blood clot found near his eye last week. Mayo Clinic medical experts performed a procedure for that blood clot.

The American Brain Tumor Association says Glioblastoma is a highly malignant and cancerous tumor. As a result, the senator could receive both chemo and radiation.

This latest diagnosis comes after the senator survived five-and-a-half years in captivity as a POW in Vietnam and a previous battle with Melanoma.

Reaction about McCain's diagnosis is coming on strong from his family and Capitol Hill.

His daughter, Meghan McCain, tweeted out a statement saying in part, "It won't surprise you to learn that in all of this, the one who is most confident and calm is my father."

Colleagues like Senator Lindsay Graham of South Carolina, say the one time Republican candidate for president is a hero.

"John is in a really good frame of mind, very appreciative of the healthcare he received and is ready to come back to do business," Sen. Graham said.

President Trump released a statement saying "Senator John McCain has always been a fighter. Melania and I send our thoughts and prayers to Senator McCain, Cindy, and their entire family. Get well soon."

A return to Washington?

RELATED: What happens if McCain can't go back to work in the Senate?

Fellow politicians on Capitol Hill say they're already counting down the days until Sen. McCain can return to Washington. However, there is no word yet on when he will be able to return to work.

McCain's office says doctors call his health excellent besides the tumor.