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Multidrug resistant proteins: P-glycoprotein and lung resistance protein expression in retinoblastoma

S Krishnakumar1, K Mallikarjuna, N Desai

  • 1Department of Ocular Pathology, Vision Research Foundation, Sankara Nethralaya, 18 College Road, Chennai-600 006,Tamil Nadu, India. drkrishnakumar_2000@yahoo.com

The British Journal of Ophthalmology
|November 19, 2004
PubMed
Abstract

Insights

Retinoblastoma tumors express multidrug resistance proteins P-glycoprotein (P-gp) and lung resistance protein (LRP) intrinsically. However, their expression does not predict chemotherapy response in these pediatric eye cancers.

Area of Science:

  • Ophthalmology
  • Pediatric Oncology
  • Molecular Biology

Background:

  • Retinoblastoma is a common childhood intraocular tumor.
  • Chemotherapy is a key treatment modality for retinoblastoma.
  • The role of multidrug resistance proteins, P-glycoprotein (P-gp) and lung resistance protein (LRP), in retinoblastoma is not well understood.

Purpose of the Study:

  • To investigate the expression of P-gp and LRP in retinoblastoma.
  • To correlate P-gp and LRP expression with clinicopathological features of retinoblastoma.
  • To assess the predictive value of P-gp and LRP expression for chemotherapy response.

Main Methods:

  • Immunohistochemistry was used to study P-gp and LRP expression in 60 retinoblastoma samples.
  • Samples included tumors with and without preoperative/postoperative chemotherapy, and with varying degrees of invasion.
  • Immunoanalysis was performed semiquantitatively.

Main Results:

  • P-gp was expressed in 38% of tumors, and LRP in 58%.
  • Expression levels of P-gp and LRP did not correlate with tumor invasion, differentiation, laterality, or response to chemotherapy.
  • P-gp and LRP were negative in three invasive tumors that later developed bone marrow metastasis.

Conclusions:

  • Retinoblastoma intrinsically expresses P-gp and LRP prior to chemotherapy.
  • Neither P-gp nor LRP expression predicted chemotherapy response in this study.
  • Further research is required to elucidate the clinical significance of P-gp and LRP expression in retinoblastoma.

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