Kenneth Y. Tsai

Don't Let the Bed Bugs Bite

The common bed bug ( Cimex lectularius ), a human pest for centuries, now persistently infests homes and hotels. Often a nuisance, it can also transmit Trypanosoma cruzi experimentally. Two groups have recently published DNA and RNA sequencing of Cimex at various stages of development. Both place Cimex genetically close to Pediculus humanas (the cause of pediculosis) and Acyrthosiphon pisum (the pea aphid). …

Melanoma Meets Microbiome

The influence of the microbiome on cancer susceptibility and therapy effectiveness has been shown. Furthermore, commensal organisms have critical roles in tuning immunity at epithelial surfaces, suggesting their potential role in regulating immunotherapy response. Sivan and colleagues compared genetically identical mice obtained from two different mouse facilities that had different gut microbiota. Interestingly, these mice reacted differently to syngeneic implanted mouse melanoma tumors, apparently because of …

Cutaneous T-Cell Lymphoma: Deep Sequencing Offers a Diagnostic Boost

Diagnosis of cutaneous T-cell lymphoma (CTCL) rests for the most part on histopathologic evaluation with adjunctive immunohistochemistry. However, considerable overlap exists between forms of chronic inflammatory dermatitis and early mycosis fungoides. Even molecular tests to measure clonality of T-cell receptor (TCR) loci are limited by relatively low sensitivity and the fact that inflammatory reactions can be clonal. Each T cell possesses a unique combination of TCR chains formed …

Chasing the Hedgehog: Drug-Resistant BCC Still Needs Hedgehog Pathway Signaling

Basal cell carcinomas (BCCs) appear universally dependent upon activated Hedgehog pathway signaling. This pathway is activated by loss of the receptor PTCH or activation of its downstream effector, Smoothened ( SMO ). Vismodegib is a small-molecule inhibitor of SMO and has been approved for the treatment of advanced BCC and basal cell nevus syndrome. While initial response rates are about 50% in advanced and metastatic BCC, resistance evolves …

Chasing the Hedgehog: Drug-Resistant BCC Still Needs

Basal cell carcinomas (BCCs) appear universally dependent upon activated Hedgehog pathway signaling. This pathway is activated by loss of the receptor PTCH or activation of its downstream effector, Smoothened ( SMO ). Vismodegib is a small-molecule inhibitor of SMO and has been approved for the treatment of advanced BCC and basal cell nevus syndrome. While initial response rates are about 50% in advanced and metastatic BCC, resistance evolves …

Sunshine on My Shoulders Makes Me High

The recent enactment of statewide bans against indoor tanning for minors is a testament to growing public acknowledgement that ultraviolet (UV) light exposure is the major risk factor for skin cancer. Nevertheless, tanning behavior is pervasive, and sunscreen use typically falls far below recommended levels. The notion that tanning may be an addictive behavior is not new. Several groups …

Skin on Alert: Skin-Resident CD8+ T Cells Drive Broad Innate Antipathogen Responses

The recent discovery and characterization of skin-resident CD8+ T cells revealed fascinating biological mechanisms showing how they enforce tissue-specific antiviral immunity. For example, a previous study (NEJM JW Dermatol May 18 2012) showed that local skin vaccination resulted in global specific immunity in skin conferred by skin-resident memory T cells (TRM). Two new studies shed more …

Blonds Have Less KIT Ligand

Many genome-wide association studies (GWAS) have focused on identifying genetic loci that determine hair pigmentation. Hair color is one of the most diverse, visible, and heavily modified of all human phenotypes, with deep cultural implications. Guenther and colleagues studied rs12821256, a single nucleotide variation (SNV) in the human genome associated with blond …

Immunotherapies in Melanoma: Genomics Reveals Determinants of Response to Anti-CTLA4 Therapy

Immune checkpoint inhibitors have successfully generated durable responses in melanoma. Ipilimumab and tremelimumab are anti-CTLA4 antibodies that

A New Mutation in Cutaneous Squamous Cell Carcinoma

Cutaneous squamous cell carcinoma (cuSCC) has only recently come under the searchlight of deep genomic analysis. Part of the difficulty in identifying