Adenosine triphosphate-binding cassette subfamily B member 1 (ABCB1) is also known by the names – permeability glycoprotein, multidrug-resistant protein 1 or cluster of differentiation 243 (CD243). It acts as an important protein that purifies foreign substances from cells. 

ABCB1 have proven their roles in cancer, stem cells and drug resistance. Numerous pharmacogenetic studies have shown the association of ABCB1 with treatment responsiveness to different agents, like chemotherapeutic and immunomodulatory agents. However, very little is known about its roles in the skin and its importance in dermatotherapeutics.

ABCB1 is expressed in the skin and its appendages while delivering and transporting drugs. It is related to the treatment responsiveness to different agents, like topical steroids, azathioprine, antihistamines, antifungal agents, biologic agents, cyclosporine, colchicine, ivermectin, methotrexate, tacrolimus, tetracycline and retinoid acids.

The genetic variation in ABCB1 is also linked with the pathogenesis of several dermatoses, like atopic dermatitis, bullous pemphigoid, Behçet disease, lichen planus, melanoma and psoriasis.

The roles of ABCB1 in dermatology need more investigation to establish the possibility of improving therapeutic efficacy through ABCB1 manipulation. Evidence favors the ABCB1 manipulation strategy to optimize treatment effects in dermatology since:

1. Variations in ABCB1 may possess the risk of adverse effects of ivermectin, azathioprine and various antihistamines.
2. Variations in ABCB1 are linked with treatment responsiveness to many crucial dermatologic agents like an antihistamine, biologic agents, colchicine, cyclosporine, methotrexate and topical steroids.
3. ABCB1 is necessary for transepidermal delivery of topical agents, particularly topical corticosteroids.
4. Increased ABCB1 expression is observed in erosive lichen planus, which may cause therapeutic refractoriness to topical corticosteroids.  
5. ABCB1 expression as well as the efficacy and safety of some medications, like cyclosporine may be impacted by food. 

However, interpreting these data may be critical as the majority of the studies were performed in cell lines instead of primary culture and in vivo studies. Since ABCB1 has been greatly investigated in malignancy, further investigation is warranted to explain their roles in non-neoplastic dermatologic diseases.

Source: Weng HJ, Tsai TF. ABCB1 in dermatology: roles in skin diseases and their treatment. J Mol Med (Berl). 2021;99(11):1527-38.