Angiotropism in primary cutaneous melanoma is associated with disease progression and distant metastases: A retrospective study of 179 cases

Lymphatic expression of the proliferation marker Ki67 is linked to sentinel node positivity, recurrence and mortality in primary cutaneous melanoma

Lymphangiogenesis is a precursor to lymphovascular invasion, and may therefore signal a higher risk of metastasis and mortality in primary cutaneous melanoma. This retrospective longitudinal study aimed to evaluate whether emergent lymphangiogenesis, as measured through co-expression of endothelial proteins with the proliferation marker Ki67, was associated with poorer prognosis in a cohort of patients with single primary cutaneous melanoma. We screened all patients with a single locally invasive primary cutaneous melanoma who received sentinel lymph node biopsy at a tertiary dermatology centre in Brisbane, Australia between 1994 and 2007. Primary melanoma sections were stained via Opal multiplex immunofluorescence, and categorized according to the presence of Ki67 within either CD31+ or D2-40+ endothelial cells. Multivariate Cox regression modelling was used to evaluate associations between endothelial Ki67 positivity and clinical outcomes, with adjustment for age, sex, Breslow depth, ulceration, and anatomical location. Overall, 264 patients were available for analysis, with a median follow-up duration of 7.1 years. The presence of D2-40+ /Ki67+ co-expression was associated with greater melanoma-specific mortality (adjusted hazard ratio [HR]: 2.03; 95% confidence interval [CI]: 1.33-3.10; p = 0.001) and recurrence (adjusted HR: 1.70; 95% CI: 1.33-3.10; p = 0.001) relative to absence. CD31+ /Ki67+ co-expression was not prognostic in this cohort. Lymphatic proliferation, as measured through D2-40+ /Ki67+ co-expression, predicted greater melanoma-specific mortality and recurrence in this cohort of primary cutaneous melanoma.

Seasonal variation in high-risk phenotypes of cutaneous malignant melanoma diagnosed in Eastern England: An observational study

BACKGROUND

Despite seasonal variation in malignant melanoma diagnosis being well described, data on the annual variation in high-risk melanomas are scarce.

OBJECTIVES

We set out to investigate the relationship between seasonality, the incidence of melanoma, and the distribution of melanoma characteristics, including Breslow thickness, ulceration, mitotic rate, lymphovascular and perineural invasion, and the presence of microsatellites.

METHODS

Primary cutaneous malignant melanomas diagnosed between 2011 and 2019 in Eastern England were identified from our prospectively maintained melanoma database (n = 2199). These were analysed by year and season of diagnosis, patient demographics, and melanoma characteristics.

RESULTS

There was a variation in rates of melanoma diagnosis across the year, with Summer having the highest incidence (p < 0.0001). There was a significant trend towards more male than female diagnosis in Winter (p = 0.0354). There were no significant seasonal trends in Breslow thickness, ulceration, tumour infiltrating lymphocytes, or mitotic rate. Multivariate analysis showed that microsatellites were more likely to be diagnosed in the Winter (OR=2.00 (1.19-3.43), p = 0.010), lymphovascular invasion significantly more likely to be diagnosed in Autumn (OR=1.78 (1.16-2.76), p = 0.009), and perineural invasion was more likely to be diagnosed in the Summer (OR=0.44 (0.23-0.79), p = 0.007).

CONCLUSIONS

These data confirm that high-risk phenotypes are associated with increasing Breslow thickness and mitotic rate. However, season variability as an independent risk factor for the phenotypes is a novel finding.

Directed movement toward, translocation along, penetration into and exit from vascular networks by breast cancer cells in 3D

We developed a computer-assisted platform using laser scanning confocal microscopy to 3D reconstruct in real-time interactions between metastatic breast cancer cells and human umbilical vein endothelial cells (HUVECs). We demonstrate that MB-231 cancer cells migrate toward HUVEC networks, facilitated by filopodia, migrate along the network surfaces, penetrate into and migrate within the HUVEC networks, exit and continue migrating along network surfaces. The system is highly amenable to 3D reconstruction and computational analyses, and assessments of the effects of potential anti-metastasis monoclonal antibodies and other drugs. We demonstrate that an anti-RHAMM antibody blocks filopodium formation and all of the behaviors that we found take place between MB-231 cells and HUVEC networks.

TFPI2 Promotes Perivascular Migration in an Angiotropism Model of Melanoma

Purpose

Angiotropism is the process by which cancer cells attach to and migrate along blood vessels to acquire vasculature, disseminate, and metastasize. However, the molecular basis for such vessel–tumor interactions has not been fully elucidated, partly due to limited experimental models. In this study, we aimed to observe and explore the molecular mechanism underlying angiotropism in melanoma.

Methods

To monitor the interactions of human melanoma cells with the vasculature in vivo, a murine coxenograft model was employed by co-injecting highly and poorly invasive melanoma cells subcutaneously. To identify key pathways and genes involved in the angiotropic phenotype of melanoma, analysis of differentially expressed genes (DEGs) and gene set enrichment analysis (GSEA) were performed. The role of tissue factor pathway inhibitor 2 (TFPI2) in angiotropism was evaluated by immunostaining, adhesion assay, shRNA, and in vivo tumorigenicity. Angiotropism and TFPI2 expression were examined in surgical specimens of melanoma by immunohistochemical staining. Data from The Cancer Genome Atlas (TCGA) were analyzed to explore the expression and prognostic implications of TFPI2 in uveal and cutaneous melanoma.

Results

Highly invasive melanoma cells spread along the branches of intratumor blood vessels to the leading edge of invasion in the coxenograft model, resembling angiotropic migration. Mechanisms underlying angiotropism were primarily associated with molecular function regulators, regulation of cell population proliferation, developmental processes, cell differentiation, responses to cytokines and cell motility/locomotion. TFPI2 downregulation weakened the perivascular migration of highly invasive melanoma cells. High levels of TFPI2 were correlated with worse and better survival in uveal and cutaneous melanoma, respectively.

Conclusion

These results provide a straightforward in vivo model for the observation of angiotropism and suggest that TFPI2 could inhibit the angiotropic phenotype of melanoma.

Replacement and desmoplastic histopathological growth patterns in cutaneous melanoma liver metastases: frequency, characteristics, and robust prognostic value

Among visceral metastatic sites, cutaneous melanoma (CM) metastasises initially to the liver in ~14-20% of cases. Liver metastases in CM patients are associated with both poor prognosis and poor response to immunotherapy. Histopathological growth patterns (HGPs) of liver metastases of the replacement and desmoplastic type, particularly from colorectal cancer and uveal melanoma (UM), may impart valuable biological and prognostic information. Here, we have studied HGP in 43 CM liver metastases resected from 42 CM patients along with other prognostic factors from three institutions. The HGPs (replacement, desmoplastic, pushing) were scored at the metastasis-liver interface with two algorithms: (1) 100% desmoplastic growth pattern (dHGP) and any (≥1%) replacement pattern (any-rHGP) and (2) >50% dHGP, >50% rHGP or mixed (<50% dHGP and/or rHGP, pushing HGP). For 1 patient with 2 metastases, an average was taken to obtain 1 final HGP yielding 42 observations from 42 patients. 22 cases (52%) had 100% dHGP whereas 20 (48%) had any replacement. Cases with rHGP demonstrated vascular co-option/angiotropism. With the development of liver metastasis, only rHGP (both algorithms), male gender and positive resection margins predicted diminished overall survival (p = 0.00099 and p = 0.0015; p = 0.034 and p = 0.024 respectively). On multivariate analysis, only HGP remained significant. 7 of 42 (17%) patients were alive with disease and 21 (50%) died with follow-up after liver metastases ranging from 1.8 to 42.2 months (mean: 20.4 months, median: 19.0 months). 14 (33%) patients with previously-treated metastatic disease had no evidence of disease at last follow up. In conclusion, we report for the first time replacement and desmoplastic HGPs in CM liver metastases and their prognostic value, as in UM and other solid cancers. Of particular importance, any rHGP significantly predicted diminished overall survival while 100% dHGP correlated with increased survival. These results contribute to a better understanding of the biology of CM liver metastases and potentially may be utilised in managing patients with these metastases.

Angiotropism, pericytic mimicry and extravascular migratory metastasis: an embryogenesis-derived program of tumor spread

Intravascular dissemination of tumor cells is the accepted mechanism of cancer metastasis. However, the phenomenon of angiotropism, pericyte mimicry (PM), and extravascular migratory metastasis (EVMM) has questioned the concept that tumor cells metastasize exclusively via circulation within vascular channels. This new paradigm of cancer spread and metastasis suggests that metastatic cells employ embryonic mechanisms for attachment to the abluminal surfaces of blood vessels (angiotropism) and spread via continuous migration, competing with and replacing pericytes, i.e., pericyte mimicry (PM). This is an entirely extravascular phenomenon (i.e., extravascular migratory metastasis or EVMM) without entry (intravasation) into vascular channels. PM and EVMM have mainly been studied in melanoma but also occur in other cancer types. PM and EVMM appear to be a reversion to an embryogenesis-derived program. There are many analogies between embryogenesis and cancer progression, including the important role of laminins, epithelial-mesenchymal transition, and the re-activation of embryonic signals by cancer cells. Furthermore, there is no circulation of blood during the first trimester of embryogenesis, despite the fact that there is extensive migration of cells to distant sites and formation of organs and tissues during this period. Embryonic migration therefore is a continuous extravascular migration as are PM and EVMM, supporting the concept that these embryonic migratory events appear to recur abnormally during the metastatic process. Finally, the perivascular location of tumor cells intrinsically links PM to vascular co-option. Taken together, these two new paradigms may greatly influence the development of new effective therapeutics for metastasis. In particular, targeting embryonic factors linked to migration that are detected during cancer metastasis may be particularly relevant to PM/EVMM.