Interval sentinel lymph nodes in melanoma: a digital pathology analysis of Ki67 expression and microvascular density

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.

Characterization of in vitro 3D cultures

Over the past decade, 3D culture models of human and animal cells have found their way into tissue differentiation, drug development, personalized medicine and tumour behaviour studies. Embryoid bodies (EBs) are in vitro 3D cultures established from murine pluripotential stem cells, whereas tumoroids are patient-derived in vitro 3D cultures. This thesis aims to describe a new implication of an embryoid body model and to characterize the patient-specific microenvironment of the parental tumour in relation to tumoroid growth rate. In this thesis, we described a high-throughput monitoring method, where EBs are used as a dynamic angiogenesis model. In this model, digital image analysis (DIA) is implemented on immunohistochemistry (IHC) stained sections of the cultures over time. Furthermore, we have investigated the correlation between the genetic profile and inflammatory microenvironment of parental tumours on the in vitro growth rate of tumoroids. The EBs were cultured in spinner flasks. The samples were collected at days 4, 6, 9, 14, 18 and 21, dehydrated and embedded in paraffin. The histological sections were IHC stained for the endothelial marker CD31 and digitally scanned. The virtual whole-image slides were digitally analysed by Visiopharm® software. Histological evaluation showed vascular-like structures over time. The quantitative DIA was plausible to monitor significant increase in the total area of the EBs and an increase in endothelial differentiation. The tumoroids were established from 32 colorectal adenocarcinomas. The in vitro growth rate of the tumoroids was followed by automated microscopy over an 11-day period. The parental tumours were analysed by next-generation sequencing for KRAS, TP53, PIK3CA, SMAD4, MAP2K1, BRAF, FGFR3 and FBXW7 status. The tumoroids established from KRAS-mutated parental tumours showed a significantly higher growth rate compared to their wild-type counterparts. The density of CD3+ T lymphocytes and CD68+ macrophages was calculated in the centre of the tumours and at the invasive margin of the tumours. The high density of CD3+ cells and the low density of CD68+ cells showed a significant correlation with a higher growth rate of the tumoroids. In conclusion, a novel approach for histological monitoring of endothelial differentiation is presented in the stem cell-derived EBs. Furthermore, the KRAS status and density of CD3+ T cells and macrophages in the parental tumour influence the growth rate of the tumoroids. Our results indicate that these parameters should be included when tumoroids are to be implemented in personalized medicine.

Next-Generation Digital Histopathology of the Tumor Microenvironment

Progress in cancer research is substantially dependent on innovative technologies that permit a concerted analysis of the tumor microenvironment and the cellular phenotypes resulting from somatic mutations and post-translational modifications. In view of a large number of genes, multiplied by differential splicing as well as post-translational protein modifications, the ability to identify and quantify the actual phenotypes of individual cell populations in situ, i.e., in their tissue environment, has become a prerequisite for understanding tumorigenesis and cancer progression. The need for quantitative analyses has led to a renaissance of optical instruments and imaging techniques. With the emergence of precision medicine, automated analysis of a constantly increasing number of cellular markers and their measurement in spatial context have become increasingly necessary to understand the molecular mechanisms that lead to different pathways of disease progression in individual patients. In this review, we summarize the joint effort that academia and industry have undertaken to establish methods and protocols for molecular profiling and immunophenotyping of cancer tissues for next-generation digital histopathology-which is characterized by the use of whole-slide imaging (brightfield, widefield fluorescence, confocal, multispectral, and/or multiplexing technologies) combined with state-of-the-art image cytometry and advanced methods for machine and deep learning.

Application of digital image analysis on histological images of a murine embryoid body model for monitoring endothelial differentiation

The in vitro 3D model established from murine pluripotential stem cells (i.e., embryoid bodies (EBs)) is a dynamic model for endothelial differentiation. The aim of the present study was to investigate whether digital image analysis (DIA) can be applied on histological sections of EBs in order to quantify endothelial differentiation over time. The EBs were established in suspension cultures for 21 days in three independent replicate experiments. At day 4, 6, 9, 14, 18, and 21, the EBs were fixed in formaldehyde, embedded in paraffin and immunohistochemically (IHC) stained for CD31. The IHC-stained slides were digitally scanned and analysed using the Visiopharm® Quantitative Digital Pathology software Oncotopix™. The EBs developed CD31+ vascular-like structures during their differentiation. The quantitative DIA of the EBs showed that the log10 values of the relative CD31+ areas increased from -0.574 ± 0.470 (mean ± SD) at day 4 to 0.093 ± 0.688 (mean ± SD) at day 21 (p < 0.001). The approach presented in this study is a fast, quantitative and reproducible alternative method for an otherwise time-consuming and observer-dependent histological investigation. The future perspectives for such a system would be implementation of a modified version of the method on different 3D cultures and IHC markers.

STAT3 Inhibition for Gastroenteropancreatic Neuroendocrine Tumors: Potential for a New Therapeutic Target?

BACKGROUND

Gastroenteropancreatic neuroendocrine tumors (GEP-NETs) are highly vascular neoplasms treated similarly, irrespective of tumor location. The expression of pro-angiogenic factors (STAT3, VEGF, and HIF-1α) and their association with adverse pathologic factors and disease recurrence following resection remains unclear.

METHODS

All patients with non-metastatic GEP-NETs who underwent curative-intent resection from 2000 to 2013 were included. Immunohistochemistry was performed for pro-angiogenic factors, Ki-67 index, and CD31 using tissue microarrays made in triplicate by a pathologist blinded to other clinicopathologic variables. Primary outcome was a 3-year recurrence-free survival (3-yrRFS); secondary outcomes were correlation of pro-angiogenic factors with Ki-67 index, adverse pathologic factors, and CD31 expression, a marker of microvascular density.

RESULTS

Of 144 GEP-NETs resected, STAT3 expression was high in 12 (8%) and low in 132 (92%) pts. High STAT3 expression was associated with worse 3-yrRFS compared to low expression (55% vs 84%; p = 0.003). High VEGF expression had a 3-yrRFS of 76% vs 82% for low expression (p = 0.09). HIF-1α expression was not associated with RFS. Ki-67 ≥ 3% was associated with worse 3-yrRFS (≥ 3%: 51% vs < 3%: 84%; p < 0.001), as was the presence of increased microvascular density (CD31 > median: 75% vs CD31 < median: 86%; p = 0.04). High STAT3 expressing tumors were more likely to have a Ki-67 ≥ 3% (42% vs 7%; p < 0.001). LVI was present in 82% of high STAT3 tumors compared to only 50% with low STAT3 (p = 0.058). CD31 expression was similar between groups (58% vs 49%; p = 0.5).

CONCLUSIONS

In resected GEP-NETs, high STAT3 expression is associated with an increased Ki-67 index, presence of lymphovascular invasion and worse 3-yr RFS. STAT3 may be a novel therapeutic target for patients undergoing resection of high-risk tumors.

Surgical management of tumor-positive interval node in melanoma patients: An observational study

The presence of interval nodes (IN) in melanoma is testified in several studies and sometimes these lymph nodes can contain metastatic disease. Currently there are no guidelines about the management of patients with tumor-positive INs.We enrolled all patients affected by melanoma who underwent sentinel lymph node biopsy (SLNB) in a single institution. All patients with tumor-positive IN underwent the lymphadenectomy of the subsequent draining lymphatic field. Prognosis of IN+-patients was compared with subjects with positive SLNB in usual field through Kaplan-Meier and multivariate Cox regression analysis.Overall 596 subjects underwent lymphoscintigraphy and one or more INs were identified in 94 (15.8%) patients. The mean number of sentinel lymph nodes (SNs) identified per patient was significantly higher in patients with INs. Macrometastasis were more common in patients with INs. Matched pair analysis testified a statistically significant better prognosis in patients with positive-INs when compared with patients with positive SNs in usual side with the same demographic and clinical characteristics. These findings were confirmed both in analysis of 10-year recurrence-free period, then in 10-years overall survival analysis.Lymphadenectomy of the lymphatic draining field beyond positive-IN testify has proved to be a safe procedure that may improve prognosis in melanoma patients with tumor-positive INs. The better prognosis of patients with tumor-positive INs undergoing lymphadenectomy may be justified by the earlier treatment of lymphatic metastases. Further multicentric comparative studies are needed to evaluate possible impact of this procedure on prognosis of melanoma patients.

Single-stage excision and sentinel lymph node biopsy in cutaneous melanoma in selected patients: a retrospective case-control study

Sometimes, diagnostic excision of a primary melanoma would already necessitate skin grafting or transposition skin flaps, especially in areas with an esthetic or functional importance. The utility of sentinel lymph node biopsy (SLNB) after skin reconstruction is controversial. We carried out a single-institution retrospective case-control study. In patients with a wide primary lesion at high clinical-dermatoscopic suspicion for invasive melanoma in anatomical region in which a reconstruction with a skin graft or a flap is required, we proposed the performance of a confocal microscopy examination and an incisional biopsy of the primary lesion. If these diagnostic methodologies confirmed the suspicion of melanoma, lymphatic mapping was performed before the wide excision (WE) of the primary lesion, and WE and SLNB were performed during the same operative procedure. The database evaluation showed 496 patients who had undergone a previous complete local excision and a subsequent SLNB (two-stage group), whereas 61 patients underwent WE and SLNB during the same surgical time (one-stage group). Histological results of the excisional biopsy confirmed the diagnosis of melanoma in all patients of the one-stage group. The false-negative rate was lower in the one-stage group (5.5%) than in the two-stage group (16.7%). Patients of the two groups showed a similar recurrence-free and overall survival period even when corrected for clinic-demographical variables. The concomitant execution of SLNB and WE after confocal microscopy examination and incisional biopsy appears to be a safe and accurate procedure in patients with a wide primary melanoma that requires a skin flaps or a skin graft to cover the residual defect.