Aggressive Squamous Cell Carcinoma in Organ Transplant Recipients

A paracrine activin A-mDia2 axis promotes squamous carcinogenesis via fibroblast reprogramming

Cancer-associated fibroblasts (CAFs) are key regulators of tumorigenesis and promising targets for next-generation therapies. We discovered that cancer cell-derived activin A reprograms fibroblasts into pro-tumorigenic CAFs. Mechanistically, this occurs via Smad2-mediated transcriptional regulation of the formin mDia2, which directly promotes filopodia formation and cell migration. mDia2 also induces expression of CAF marker genes through prevention of p53 nuclear accumulation, resulting in the production of a pro-tumorigenic matrisome and secretome. The translational relevance of this finding is reflected by activin A overexpression in tumor cells and of mDia2 in the stroma of skin cancer and other malignancies and the correlation of high activin A/mDia2 levels with poor patient survival. Blockade of this signaling axis using inhibitors of activin, activin receptors, or mDia2 suppressed cancer cell malignancy and squamous carcinogenesis in 3D organotypic cultures, ex vivo, and in vivo, providing a rationale for pharmacological inhibition of activin A-mDia2 signaling in stratified cancer patients.

Outcomes in intermediate-risk squamous cell carcinomas treated with Mohs micrographic surgery compared with wide local excision

BACKGROUND

Brigham and Women's Hospital stage T2a squamous cell carcinomas, demonstrating a single high-risk feature, have a low risk of metastasis and death but an increased risk of local recurrence. Little evidence exists for the best treatment modality and associated outcomes in T2a squamous cell carcinoma.

OBJECTIVE

We aimed to compare outcomes for T2a squamous cell carcinoma treated by Mohs micrographic surgery compared with wide local excision with permanent sections.

METHODS

Retrospective review of an institutional review board-approved single-institution registry of T2a squamous cell carcinoma.

RESULTS

Three hundred sixty-six primary T2a tumors were identified, including 240 squamous cell carcinomas (65.6%) treated with Mohs micrographic surgery and 126 (34.4%) treated with wide local excision. A total of 32.5% of patients were immunosuppressed and mean oncologic follow-up was 2.8 years. Local recurrence was significantly more likely after wide local excision (4.0%) than after Mohs micrographic surgery (1.2%) (P = .03). Multiple logistic regression demonstrated immunocompromised state (odds ratio [OR] 5.1; 95% confidence interval [CI] 1.1-23.3; P = .03) and wide local excision (OR 4.8; 95% CI 1.1-21.6; P = .04) associated with local recurrence; and wide local excision (OR 7.8; 95% CI 2.4-25.4; P < .001), high-risk head and neck location (OR 8.3; 95% CI 1.8-38.7; P = .004), and poor histologic differentiation (OR 4.7; 95% CI 1.4-15.4; P = .03) associated with poor outcomes (overall recurrence or disease-specific death).

CONCLUSION

Mohs micrographic surgery provides improved outcomes in Brigham and Women's Hospital T2a squamous cell carcinoma.

The Role of the Immune System in Cutaneous Squamous Cell Carcinoma

Cutaneous squamous cell carcinoma (cSCC) is the second most common skin cancer. In immunosuppressed populations it is a source of considerable morbidity and mortality due to its enhanced recurrence and metastatic potential. In common with many malignancies, leucocyte populations are both protective against cancer development and also play a role in 'sculpting' the nascent tumor, leading to loss of immunogenicity and tumor progression. UV radiation and chronic viral carriage may represent unique risk factors for cSCC development, and the immune system plays a key role in modulating the response to both. In this review, we discuss the lessons learned from animal and ex vivo human studies of the role of individual leucocyte subpopulations in the development of cutaneous SCC. We then discuss the insights into cSCC immunity gleaned from studies in humans, particularly in populations receiving pharmacological immunosuppression such as transplant recipients. Similar insights in other malignancies have led to exciting and novel immune therapies, which are beginning to emerge into the cSCC clinical arena.