Dr. Sita Withers
Assistant Professor
Veterinary Clinical Sciences (VCS)

After graduating with a veterinary degree from the University of Melbourne Australia in 2008, Sita practiced in a mixed animal clinic in Far North Queensland for a year. She then returned to Melbourne to pursue a small animal internship, and subsequently moved to California to undertake a medical oncology residency at UC Davis. During her residency she developed a keen interest in cancer research, which prompted her pursuit of a PhD after becoming board certified in veterinary medical oncology. Her PhD in Integrative Pathobiology enabled her to develop skills in pathology, immunology, and flow cytometry. The focus of her research is to investigate the immune microenvironment in canine and human osteosarcoma, and to facilitate the translation of bench-top findings into clinical advancements for osteosarcoma patients of both species.

Teaching Interests:
Clinical instruction; Communication

Research Interests:
Comparative cancer immunology; Tumor microenvironment; Metastasis

 Awards & Honors:
  • 2008 Graduated with honours
  • PhD University of California- Davis
  • BVSc University of Melbourne
Journal Article, Academic Journal:
  • Metastatic immune infiltrates correlate with those of the primary tumour in canine osteosarcoma., Withers, Sita; York, D; Choi, J; Woolard, K; Laufer-Amorim, R; Sparger, E; Burton, J; McSorley, S; Monjazeb, A; Murphy, W; Canter, R; Rebhun, R, 2019, Veterinary and comparative oncology
  • Paradoxical effects of obesity on T cell function during tumor progression and PD-1 checkpoint blockade., Wang, Z; Aguilar, E; Luna, J; Dunai, C; Khuat, L; Le , C; Mirsoian, A; Minnar, C; Stoffel, K; Sturgill, I; Grossenbacher, S; Withers, Sita; Rebhun, R; Hartigan-O'Connor, D; Méndez-Lagares, G; Tarantal, A; Isseroff, R; Griffith, T; Schalper, K; Merleev, A; Saha, A; Maverakis, E; Kelly, K; Aljumaily, R; Ibrahimi, S; Mukherjee, S; Machiorlatti, M; Vesely, S; Longo, D; Blazar, B; Canter, R; Murphy, W; Monjazeb, A, 2019, Nature medicine , Volume: 25, Number: 1, Pages: 141-151
  • In vitro and in vivo activity of liposome-encapsulated curcumin for naturally occurring canine cancers., Withers, Sita; York, D; Johnson, E; Al-Nadaf, S; Skorupski, K; Rodriguez, Jr, C; Burton, J; Guerrero, T; Sein, K; Wittenburg, L; Rebhun, R, 2018, Veterinary and comparative oncology , Volume: 16, Number: 4, Pages: 571-579
  • Multi-color flow cytometry for evaluating age-related changes in memory lymphocyte subsets in dogs., Withers, Sita; Moore, P; Chang, H; Choi, J; McSorley, S; Kent, M; Monjazeb, A; Canter, R; Murphy, W; Sparger, E; Rebhun, R, 2018, Developmental and comparative immunology , Volume: 87, Pages: 64-74
  • Association of macrophage and lymphocyte infiltration with outcome in canine osteosarcoma., Withers, Sita; Skorupski, K; York, D; Choi, J; Woolard, K; Laufer-Amorim, R; Sparger, E; Rodriguez, C; McSorley, S; Monjazeb, A; Murphy, W; Canter, R; Rebhun, R, 2018, Veterinary and comparative oncology
  • Enrofloxacin enhances the effects of chemotherapy in canine osteosarcoma cells with mutant and wild-type p53., York, D; Withers, Sita; Watson, K; Seo, K; Rebhun, R, 2017, Veterinary and comparative oncology , Volume: 15, Number: 3, Pages: 1087-1100
  • Evaluation of optimal water fluoridation on the incidence and skeletal distribution of naturally arising osteosarcoma in pet dogs., Rebhun, R; Kass, P; Kent, M; Watson, K; Withers, Sita; King, A, 2017, Veterinary and comparative oncology , Volume: 15, Number: 2, Pages: 441-449
  • Canine cancer immunotherapy studies: linking mouse and human., Park, J; Withers, Sita; Modiano, J; Kent, M; Chen, M; Luna, J; Sparger, E; Rebhun, R; Monjazeb, A; Murphy, W; Canter, R, 2016, Journal for immunotherapy of cancer , Volume: 4, Pages: 97
  • Management of an invasive and metastatic Sertoli cell tumor with associated myelotoxicosis in a dog., Withers, Sita; Lawson, C; Burton, A; Rebhun, R; Steffey, M, 2016, The Canadian veterinary journal = La revue veterinaire canadienne , Volume: 57, Number: 3, Pages: 299-304
  • Paraneoplastic hypertrophic osteopathy in 30 dogs., Withers, Sita; Johnson, E; Culp, W; Rodriguez, Jr, C; Skorupski, K; Rebhun, R, 2015, Veterinary and comparative oncology , Volume: 13, Number: 3, Pages: 157-65
  • BMI1 is expressed in canine osteosarcoma and contributes to cell growth and chemotherapy resistance., Shahi, M; York, D; Gandour-Edwards, R; Withers, Sita; Holt, R; Rebhun, R, 2015, PloS one , Volume: 10, Number: 6, Pages: e0131006
  • Fasting Reduces the Incidence of Delayed-Type Vomiting Associated with Doxorubicin Treatment in Dogs with Lymphoma., Withers, Sita; Kass, P; Rodriguez, Jr, C; Skorupski, K; O'Brien, D; Guerrero, T; Sein, K; Rebhun, R, 2014, Translational oncology
  • Evaluation of a single subcutaneous infusion of carboplatin as adjuvant chemotherapy for dogs with osteosarcoma: 17 cases (2006-2010)., Simcock, J; Withers, Sita; Prpich, C; Kuntz, C; Rutland, B, 2012, Journal of the American Veterinary Medical Association , Volume: 241, Number: 5, Pages: 608-14