Background The human papillomavirus (HPV) is an important aetiological agent in cancer but its involvement in retinoblastomas (RBs) is controversial.
Methods 64 formalin-fixed paraffin-embedded tissue blocks and 19 fresh-frozen specimens were subjected to multiplex PCR using PGMY09/11 primers, HPV genotyping, non-isotopic in situ hybridisation and immunohistochemistry for pRb and p16INK4a.
Results 24% of RBs contained HPV DNA. 90% of HPV genotypes were of high-risk (HR) type and 10% were of intermediate-risk (IR) type. HR HPVs 45, 59, 68 and 52 were detected for the first time, as were IR HPVs 82 and 73. There was only one HPV 18-positive case. Interestingly, no low-risk genotypes were identified. Nine formalin-fixed paraffin-embedded HPV-positive cases showed nuclear HPV positivity by non-isotopic in situ hybridisation. Immunohistochemistry did not show pRb expression in 67% of cases. 34% expressed nuclear p16INK4a, of which 20 cases were also positive for HPV by multiplex PCR. A statistically significant association between HPV and pRb expression status was observed (p=0.0001).The association of HPV with p16INK4a expression was also statistically significant (p=0.0001).
Conclusions While the presence of HPV in a subset of RB was demonstrated, its role in carcinogenesis needs further elucidation.
- human papillomavirus
- in situ hybridisation
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RSJ and RVK contributed equally to this work.
Funding This work was funded by the Indian Council of Medical Research, New Delhi, India (Project No: 5/13/47/05/NCDIII).
Competing interests None.
Ethics approval Ethics approval was obtained from the Institute Ethics Committee, Kidwai Memorial Institute of Oncology, Bangalore, Karnataka, India.
Provenance and peer review Not commissioned; externally peer reviewed.