Abnormal AP-1 protein expression in primary cutaneous B-cell lymphomas

Authors

  • X. Mao,

    1. Skin Tumour Unit and *Dermatopathology Laboratory, St John’s Institute of Dermatology, St Thomas’ Hospital, King’s College London, U.K.
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  • G. Orchard

    1. Skin Tumour Unit and *Dermatopathology Laboratory, St John’s Institute of Dermatology, St Thomas’ Hospital, King’s College London, U.K.
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  • Conflicts of interest
    None declared.

Xin Mao.
E-mail: mxmayo@yahoo.co.uk

Summary

Background  Primary cutaneous B-cell lymphoma (PCBCL) consists mainly of primary cutaneous marginal zone B-cell lymphoma (PCMZL), primary cutaneous follicle centre lymphoma (PCFCL) and primary cutaneous large B-cell lymphoma, leg type (PCLBCL-LT). The activator protein 1 (AP-1) transcription factor includes JUN, FOS and other family members.

Objectives  To assess the expression pattern of AP-1 transcription factors in PCBCL.

Methods  We analysed paraffin tissue sections from nine cases of PCMZL, seven PCFCL, six PCLBCL-LT and two unspecified PCBCL cases by using immunohistochemistry with antibodies against c-JUN, JUNB, JUND, c-FOS, RAF1, αPAK, CD30 and CCND1.

Results  A positive staining for JUND (++) was observed in six cases of PCFCL (86%), five PCLBCL-LT (83%) and five PCMZL (56%). Positive CCND1 protein expression was present in four cases of PCLBCL-LT (67%), four PCFCL (57%) and four PCMZL (44%), and the two unspecified PCBCL cases. Expression of αPAK protein was seen in three cases of PCLBCL-LT (50%), two PCMZL (22%) and one PCFCL. However, c-JUN, c-FOS and RAF1 protein were rarely expressed in the PCBCL cases analysed; JUNB and CD30 protein expression was absent in these cases.

Conclusions  These findings suggest that the presence of abnormal AP-1 protein expression is associated with upregulation of JUND, CCND1 and αPAK and downregulation of JUNB in PCBCL.

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