The role of cyclin D1 and vascular endothelial growth factor (VEGF) in radiotherapy response of undifferentiated nasopharyngeal carcinoma

Abstract

Nasopharyngeal carcinoma (NPC) has a high incidence and mortality rate in Southeast
Asia included in Indonesia. Radioresistance is a major obstacle for a successful treatment
of NPC. DNA repair in the cell cycle and angiogenesis factors affect the response of
tumor cells to radiotherapy. Cyclin D1 that functions in the cell cycle process and vascular
endothelial growth factor (VEGF) as an angiogenesis factor are considered to play a
role in the occurrence of radioresistance. The objective of this study was to evaluate
the association between cyclin D1 and VEGF expressions with radiotherapy response
in undifferentiated NPC. This study used a retrospective case control analysis design.
Secondary data from medical records of patients diagnosed as undifferentiated NPC who
received a complete radiotherapy at the Department of Radiation Oncology, Dr. Hasan
Sadikin General Hospital, Bandung. There were 44 samples divided into radiosensitive
(22 samples) and radioresistant (22 samples) groups. Immunohistochemical examination
of cyclin D1 and VEGF expressions was performed on paraffin blocks of patients’
nasopharyngeal biopsy. Data analysis used Chi-Square test with p ≤0.05. Cyclin D1 was
expressed strongly in 86.4% of the radioresistant group and 59.1% in the radiosensitive
group (p<0.05), VEGF was strongly expressed in 77.3% of the radioresistant group and
54.5% in the radiosensitive group (p>0.05). In conclusion, there is significant association
between cyclin D1 expression with radiotherapy response in undifferentiated NPC.
However, there is no association between VEGF expression with radiotherapy response.