Upper school science teacher Walt Werner has taken a medical leave after being diagnosed this past June with Non-Hodgkin’s lymphoma, a cancer of the lymph tissue.

Doctors are confident that he will be in the hospital for a stem cell transplant within a month.

The school has been very supportive and Werner hopes to be back by the beginning of second semester, his wife, history teacher Francine Werner, said.

Upper school science department head Larry Axelrod and science teacher Dietrich Schuhl are covering Werner’s AP Biology classes during his absence.

Substitute teacher William Peet will cover Werner’s Human Anatomy and Physiology classes for the remainder of the semester. Axelrod asked Peet to substitute because he used to teach those same courses when he was a member of the faculty from 1979-2003.

“Harvard-Westlake is a great place to teach, great students, great faculty and staff and great facilities,” Peet said.

Peet mainly taught regular, honors and AP Biology.

“I love biology and I hope to engender the same love for it in my students,” Peet said.

Although he is currently substituting for Werner, Peet has been spending his retirement “keeping busy with a wide variety of projects.”