Longtime Tinley Park Mayor Ed Zabrocki will resign office effective June 1, citing a recurrence of abdominal cancer.

“I had cancer 10 years ago and it has returned,” Zabrocki told the Chicago Sun-Times on Wednesday afternoon.

Zabrocki said he is scheduled to undergo an intensive round of treatment starting later this month, which will last 10 weeks.

The mayor said reinforcing his decision was the need to help care for his granddaughter, who is also ill.

The announcement came at the Tinley Park business breakfast Wednesday morning with about 300 attendees, according to a report in the Chicago Tribune.

“During the last 10 days of April, Emily [Zabrocki’s wife] and I took some time for ourselves to evaluate and prioritize our futures,” Zabrocki said at the meeting.

City Hall confirmed the pending resignation Wednesday morning, but would give no further details.

Zabrocki, 73, has been mayor of Tinley Park since 1981.