Comprehensive clinicopathological and molecular analysis of primary malignant melanoma of the oesophagus

Comprehensive molecular findings in primary malignant melanoma of the esophagus: A multicenter study

Primary malignant melanoma of the esophagus (PMME) is an extremely rare but highly aggressive malignancy with a poor prognosis. Due to the scarcity of driver gene alterations, there is a need for more clinical data to comprehensively depict its molecular alterations. This study reviewed 26 PMME cases from three medical centers. Hybrid capture-based targeted sequencing of 295 and 1021 genes was performed in 14 and 12 cases, respectively. We found that PMME patients had a relatively low tumor mutation burden (median, 2.88 mutations per Mb) and were simultaneously accompanied by mutations in genes such as KIT (6/26, 23%), TP53 (6/26, 23%), SF3B1 (4/26, 15%), and NRAS (3/26, 12%). KIT, NRAS, and BRAF were mutually exclusive, and SF3B1 co-occurred with KIT mutation and amplification. The most common pathways affected were the mitogen-activated protein kinases and DNA damage response (DDR) pathways. Stage IV was a risk factor for both progression-free survival (hazard ratio [HR] = 5.14, 95% confidence interval [CI] = 1.32-19.91) and overall survival (OS), HR = 4.33, 95% CI = 1.22-15.30). Treatment with immune-checkpoint inhibitors (ICIs) was an independent factor for favorable OS (HR = 0.10, 95% CI = 0.01-0.91). Overall, PMME is a complex malignancy with diverse gene alterations, especially with harboring DDR alterations for potentially response from ICIs.

Primary malignant melanoma of the esophagus: A case report

BACKGROUND

Primary malignant melanoma of the esophagus (PMME) is a rare malignant disease whose clinical and molecular pathological features, origin and pathogenesis, diagnosis and treatment have not been elucidated.

CASE SUMMARY

In this paper, we report a case of a 73-year-old male with PMME. The patient complained of progressive dysphagia accompanied by substantial weight loss. Gastroscopy revealed a purple black bulging-type mass in the lower esophagus with easy bleeding on contact and scattered satellite lesions in the stomach. Histopathological biopsy revealed melanocytes in the esophageal mucosa. Physical examination and multidisciplinary consultation led to diagnostic exclusion of melanoma originating in other organs, such as the skin. Through this case report and literature review, we aimed to describe the clinical and molecular pathological features of PMME and summarize possible pathways of pathogenesis as well as cutting-edge therapeutic advances.

CONCLUSION

PMME is a rare malignancy of the esophagus with a poor prognosis. Clinicians should raise their awareness and be able to identify early lesions.

Two unique cases of metastatic malignant melanoma of the gastrointestinal tract

INTRODUCTION AND IMPORTANCE

Gastrointestinal tract (GIT) is a common site for malignant melanoma metastasis, with small bowel being the most common. It is usually difficult to diagnose at an early stage because of the anatomical location of the disease. It is also challenging for pathologists to diagnose due to the small amount of biopsy samples. Survival rates of melanoma patients with distant metastasis are very poor.

CASE PRESENTATION

This study presents two males, aged 67 and 69 years old, who have metastatic melanoma within the GIT. One was metastasis to the esophagus and another with metastasis to the jejunum presenting as intraluminal masses. Their clinical history and pathologic features of the metastasis are evaluated to give an insight into this disease.

CLINICAL DISCUSSION

Gastrointestinal melanoma is hard to detect due to its anatomical location and limited ability to biopsy. Typically, they present at an advanced stage when diagnosed. Approximately 60 % of patients with cutaneous melanoma will have GIT metastasis at the time of autopsy. The small bowel was found to have an affinity for malignant melanoma due to the expression of the CCR9 ligand, CCL25. BRAF mutations are much less observed in GIT mucosal melanomas as compared to cutaneous melanomas. Furthermore, AKAP13-NTRK3 fusion has been reported specifically in the GIT mucosal melanomas. NTRK fusions in general can be observed in metastatic melanomas and have been reported in GIT metastatic melanomas.

CONCLUSION

GIT malignant melanomas are difficult to detect due to their anatomical location, with poor prognosis, and have a unique genetic profile.

Comprehensive genomic analysis of primary malignant melanoma of the esophagus reveals similar genetic patterns compared with epithelium-associated melanomas

Primary malignant melanoma of the esophagus (PMME) is an exceedingly rare disease with a poor prognosis. The etiology of PMME remains largely unknown and genetic characteristics are yet to be clarified, essential for identifying potential therapeutic targets and defining treatment guidelines. Here, we performed whole-exome sequencing on 47 formalin-fixed paraffin-embedded specimens from 18 patients with PMME, including 23 tumor samples, 6 metastatic lymph nodes, and 18 tumor-adjacent normal tissues. The genomic features of PMME were comprehensively characterized, and comparative genomic analysis was further performed between these specimens and 398 skin cutaneous melanomas (SKCM), 67 non-esophagus mucosal melanomas (NEMM), and 79 uveal melanomas (UVM). In the PMME cohort, recurrently mutated driver genes, such as MUC16, RANBP2, NRAS, TP53, PTPRT, NF1, MUC4, KMT2C, and BRAF, were identified. All RANBP2 mutations were putatively deleterious, and most affected samples had multipoint mutations. Furthermore, RANBP2 showed parallel evolution by multiregional analysis. Whole-genome doubling was an early truncal event that occurred before most driver mutations, except for in TP53. An ultraviolet radiation-related mutational signature, SBS38, was identified as specific to epithelial melanomas and could predict inferior survival outcomes in both PMME and SKCM patients. Comparing the mutational and copy number landscapes between PMME and other subtypes of melanoma revealed that PMME has a similar genomic pattern and biological characteristics to SKCM. In summary, we comprehensively defined the key genomic aberrations and mutational processes driving PMME and suggested for the first time that PMME may share similar genomic patterns with SKCM; therefore, patients with rare melanomas, such as PMME, may benefit from the current treatment used for common cutaneous melanoma.

Longitudinal genomic alternations and clonal dynamics analysis of primary malignant melanoma of the esophagus

Primary malignant melanoma of the esophagus (PMME) is a rare gastrointestinal melanoma with a high rate of recurrence and metastasis. The standard of care for PMME has not been established yet due to a lack of understanding of its clinical and molecular pathogenesis. Thus, we performed genomic profiling on a recurrent PMME case to seek novel opportunities for the management of this rare disease. Between 2013 and 2016, 6 tissue samples including 3 from the primary tumors, 2 from the relapsed tumors, and 1 from a normal control were collected from a patient diagnosed with PMME and were subjected to whole-exome sequencing to track the dynamic genetic changes. Additionally, we also analyzed a cohort of 398 samples obtained from the TCGA skin cutanesous melanoma (TCGA-SKCM) dataset to assess the frequency and determine the clinical implications of genomic events found in the presented study. ARHGAP35 (p.L1022M) was the only mutation shared across temporal PMME lesions. The PMME samples showed higher levels of genetic instability and intra-tumor heterogeneity. They also shared several concordant copy number variations (CNV). All lesions were concordant with the evolution trajectory, and shrinkage of the founding clone caused the subclonal population to become dominant in PT1c, which was likely the reason behind metastatic seeding. ARHGAP35 mutations were found in 6% of the TCGA-SKCM cohort samples. The presence of the mutations was associated with poor progression-free survival (PFS) by both univariate and multivariate Cox regression analyses. Our study showed that the primary tumor clone disseminates earlier in PMME. This highlights the need to understand the mechanism involved in the early PMME recurrence to optimize treatment.

The Thousand Faces of Malignant Melanoma: A Systematic Review of the Primary Malignant Melanoma of the Esophagus

Primary Malignant Melanoma of the Esophagus (PMME) is an extremely rare cancer of the esophagus, accounting for 0.1−0.8% of all oro-esophageal cancers and <0.05% of all melanoma subtypes, with an estimated incidence of 0.0036 cases per million/year. We conduct a careful analysis of the literature starting from 1906 to the beginning of 2022, searching the PubMed, Science.gov, Scopus and Web of Science (WoS) databases. A total of 457 records were initially identified in the literature search, of which 17 were duplicates. After screening for eligibility and inclusion criteria, 303 publications were ultimately included, related to 347 patients with PMME. PMME represents a very rare entity whose very existence has been the subject of debate for a long time. Over time, an increasing number of cases have been reported in the literature, leading to an increase in knowledge and laying the foundations for a discussion on the treatment of this pathology, which still remains largely represented by surgery. In recent times, the possibility of discovering greater mutations in gene hotspots has made it possible to develop new therapeutic strategies of which nivolumab is an example. Future studies with large case series, with clinicopathological and molecular data, will be necessary to improve the outcome of patients with PMME.

Relevance of BRAF Subcellular Localization and Its Interaction with KRAS and KIT Mutations in Skin Melanoma

Although skin melanoma (SKM) represents only one-quarter of newly diagnosed skin malignant tumors, it presents a high mortality rate. Hence, new prognostic and therapeutic tools need to be developed. This study focused on investigating the prognostic value of the subcellular expression of BRAF, KRAS, and KIT in SKM in correlation with their gene-encoding interactions. In silico analysis of the abovementioned gene interactions, along with their mRNA expression, was conducted, and the results were validated at the protein level using immunohistochemical (IHC) stains. For IHC expression, the encoded protein expressions were checked on 96 consecutive SKMs and 30 nevi. The UALCAN database showed no prognostic value for the mRNA expression level of KRAS and BRAF and demonstrated a longer survival for patients with low mRNA expression of KIT in SKMs. IHC examinations of SKMs confirmed the UALCAN data and showed that KIT expression was inversely correlated with ulceration, Breslow index, mitotic rate, and pT stage. KRAS expression was also found to be inversely correlated with ulceration and perineural invasion. When the subcellular expression of BRAF protein was recorded (nuclear vs. cytoplasmatic vs. mixed nucleus + cytoplasm), a direct correlation was emphasized between nuclear positivity and lymphovascular or perineural invasion. The independent prognostic value was demonstrated for mixed expression of the BRAF protein in SKM. BRAF cytoplasmic predominance, in association with KIT's IHC positivity, was more frequently observed in early-stage nonulcerated SKMs, which displayed a low mitotic rate and a late death event. The present study firstly verified the possible prognostic value of BRAF subcellular localization in SKMs. A low mRNA expression or IHC cytoplasmic positivity for KIT and BRAF might be used as a positive prognostic parameter of SKM. SKM's BRAF nuclear positivity needs to be evaluated in further studies as a possible indicator of perineural and lymphovascular invasion.

Knockdown of GBAS regulates esophageal cancer cell viability and apoptosis

Esophageal cancer (EC) is the sixth leading cause of cancer‑related mortality worldwide, with the incidence gradually increasing each year. Therefore, further clarifying the mechanism underlying the development of EC may be beneficial for identifying novel biomarkers and targets for its treatment. The present study aimed to determine the functional roles of glioblastoma‑amplified sequence (GBAS), a newly identified gene that has been reported to play crucial roles in multiple types of cancer, including in the malignant behavior of EC cells, such as cell viability, colony formation, cell apoptosis and cell cycle progression. The results of the present study revealed that, in vitro, the knockdown of GBAS significantly suppressed cell viability and colony formation in TE‑1 and KYSE‑150 cell lines, using a Celigo cell count analysis and colony formation assay respectively, whereas the apoptotic rate of EC cells was significantly increased by the knockdown of GBAS using Annexin V APC staining. Furthermore, following GBAS knockdown, the cell cycle progression of TE‑1 and KYSE‑150 cells was arrested in the G1 phase using PI staining. In conclusion, the findings of the present study suggested that GBAS may serve a role in EC by regulating cell viability, apoptosis and cell cycle progression.