Desmoid tumour in an inguinal hernia in a patient with a previous diagnosis of melanoma.

A 68-year-old man, without a family history of cancer, was treated for primary cutaneous melanoma of the scalp. Two years later, a right lateral cervical lymph recurrence was observed and he was treated with lymphadenectomy and adjuvant nivolumab for 1 year. Four years from the initial melanoma diagnosis, a computer tomography scan showed a solid nodular lesion of 26 × 40 × 75 mm inside the previously known inguinoscrotal hernia. A new recurrence of melanoma was the most probable diagnosis and a right inguinal hernioplasty was performed. Notably, the histopathological examination revealed a mesenteric fibromatosis with the typical immunohistochemical pattern (strong nuclear staining of ß-catenin). Interestingly, this represents the first case of a patient with a mesenteric desmoid tumour presenting as an inguinal hernia masking a cutaneous melanoma recurrence.

Implementation of a virtual multicenter gastrointestinal tumor board to reduce cancer disparities in Argentina.

Given the increasing complexity of cancer care, multidisciplinary tumor boards have become essential in daily clinical oncology practice. The Project Extension for Community Healthcare Outcomes (ECHO) initiative developed an innovative telementoring model using a "hub and spoke" design consisting of a team of experts (hub) that offers a full service to multiple participants (the spokes) during regularly scheduled sessions discussing patients' clinical cases. The Alexander Fleming Cancer Institute in Buenos Aires was the first hub in Latin America to implement Project ECHO for gastrointestinal tumors. In our 3-year experience, 80 patients from 37 centers were evaluated within Project ECHO and a range of three to five cases were discussed in each meeting. From our perspective, the impact of this novel approach was a remarkable strategy to reduce care disparities by equalizing access to high-quality medical knowledge in a multidisciplinary environment for medical discussions. Additionally, it was shown to have a cost-effective impact directly on the patients and the local health system, since relevant costs were saved after unnecessary treatments, studies and travel expenses were avoided.

Phenotypic and Functional Dysregulated Blood NK Cells in Colorectal Cancer Patients Can Be Activated by Cetuximab Plus IL-2 or IL-15.

The clinical outcome of colorectal cancer (CRC) is associated with the immune response; thus, these tumors could be responsive to different immune therapy approaches. Natural killer (NK) cells are key antitumor primary effectors that can eliminate CRC cells without prior immunization. We previously determined that NK cells from the local tumor environment of CRC tumors display a profoundly altered phenotype compared with circulating NK cells from healthy donors (HD). In this study, we evaluated peripheral blood NK cells from untreated patients and their possible role in metastasis progression. We observed profound deregulation in receptor expression even in early stages of disease compared with HD. CRC-NK cells displayed underexpression of CD16, NKG2D, DNAM-1, CD161, NKp46, and NKp30 activating receptors, while inhibitory receptors CD85j and NKG2A were overexpressed. This inhibited phenotype affected cytotoxic functionality against CRC cells and interferon-γ production. We also determined that NKp30 and NKp46 are the key receptors involved in detriment of CRC-NK cells' antitumor activity. Moreover, NKp46 expression correlated with relapse-free survival of CRC patients with a maximum follow-up of 71 months. CRC-NK cells also exhibited altered antibody-dependent cellular cytotoxicity function responding poorly to cetuximab. IL-2 and IL-15 in combination with cetuximab stimulated NK cell, improving cytotoxicity. These results show potential strategies to enhance CRC-NK cell activity.

Non-surgical management of rectal cancer. Series of 68 cases, long follow up in two leading centres in Argentina.

BACKGROUND: The non-surgical management in a selected group of rectal cancer patients has shown promising results with adequate follow up. AIMS: describing the results of the non-surgical management in patients with complete clinical response, with a close follow up. METHODS: Between 2006 and 2015, patients with rectal cancer, stages I-III, without metastasis, treated with neoadjuvant CRT/CT, who had clinical complete response were included. CCR was defined through digital palpation, endoscopy-based criteria and MRI. Follow up was set according to institutional guidelines. RESULTS: 68 patients were included. Initial stage was assessed with MRI in 55/68 pts and EUS 11/68. Considering the recurrence risk factors 57.6% (29/68) were T2-3ab N0, 3.3% (2/68) were T4N0, 29% (20/68) were T3-4 N1-2, with 39.7% with positive MRC. Mean distance to the anal margin was 3cm. Chemoradiation included radiotherapy at 50.4cGy, and concurrent capecitabine. In 22% a fluoropirimidine and oxaliplatin-based schema was used as induction therapy. Median follow up was 37.5 months and response assessment time 9 weeks (5-19). Eleven patients recurred, 6 endoluminally, 3 developed mesorectal recurrence, and two distant failure. Five years DFS and OS were 76.3% and 93.8%. CONCLUSIONS: conservative management was feasible with close follow up in leading cancer centres. In this series, DFS and OS were comparable to the data already reported in the literature.

Observational study of patients with gastroenteropancreatic and bronchial neuroendocrine tumors in Argentina: Results from the large database of a multidisciplinary group clinical multicenter study.

Neuroendocrine tumors (NET) include a spectrum of malignancies arising from neuroendocrine cells throughout the body. The objective of this clinical investigation of retrospectively and prospectively collected data was to describe the prevalence, demographic data, clinical symptoms and methods of diagnosis of NET and the treatment and long-term follow-up of patients with NET. Data were provided by the participating centers and assessed for consistency by internal reviewers. All the cases were centrally evaluated (when necessary) by the pathologists in our group. The tissue samples were reviewed by hematoxylin and eosin and immunohistochemical staining techniques to confirm the diagnosis of NET. In total, 532 cases were documented: 461 gastroenteropancreatic-NET (GEP-NET) and 71 bronchial NET (BNET). All the tumors were immunohistochemically defined according to the World Health Organization (WHO) and European Neuroendocrine Tumor Society criteria. The most common initial symptoms in GEP-NET were abdominal pain, diarrhea, bowel obstruction, flushing, gastrointestinal bleeding and weight loss. The most common tumor types were carcinoid (58.0%), non-functional pancreatic tumor (23.0%), metastatic NET of unknown primary (16.0%) and functional pancreatic tumor (3.0%). Of the BNET, 89.0% were typical and 11.0% atypical carcinoids. Of the patients with GEP-NET, 59.2% had distant metastasis at diagnosis. The locations of the primary tumors in GEP-NET were the small bowel (26.9%), pancreas (25.2%), colon-rectum (12.4%), appendix (7.6%), stomach (6.9%), esophagus (2.8%), duodenum (2.0%) and unknown primary (16.3%). The histological subtypes based on the WHO classification were well-differentiated NET (20.1%), well-differentiated neuroendocrine carcinomas (66.5%) and poorly differentiated neuroendocrine carcinomas (10.3%). Overall, 67.3% of the patients underwent surgery, 41.2% with curative intent and 26.1% for palliative purposes. The 5-year survival rates were 65.1% (95% confidence interval, 58.0-71.4%) in GEP-NET and 100.0% in typical carcinoid of the lung. This observational, non-interventional, longitudinal study aimed to accumulate relevant information regarding the epidemiology, clinical presentation and current practices in the treatment of NET patients in Argentina, providing insight into regional differences and patterns of care in this heterogeneous disease.

Altered phenotype in peripheral blood and tumor-associated NK cells from colorectal cancer patients.

Despite NK cells being originally identified because of their ability to kill tumor cells in vitro, only limited information is available on NK cells infiltration of malignant tumors, especially in humans. NK cells infiltrating human colorectal carcinomas (CRCs) were analyzed to identify their potential protective role in an antitumor immune response. The expression and function of relevant molecules were analyzed from different sources, comparing tumor-associated NK cells (TANKs) with autologous peripheral blood NK cells (PB-NKs) from CRC patients-the latter in comparison with PB-NKs from normal donors. TANKs displayed a profound alteration of their phenotype with a drastic reduction of NK cell receptor expression. Co-culture experiments showed that CRC cells produce modulation in NK phenotype and functionality. Moreover, PB-NKs from CRC patients also exhibited an altered phenotype and profound defects in the ability to activate degranulation and IFN-γ production. For the first time, TANK and PB-NK cells from CRC patients have been characterized. It is shown that they are not capable of producing relevant cytokines and degranulate. Taken together, our results suggest that NK cells from CRC patients present alterations of phenotype and function therefore supporting the progression of cancer.

Metallothionein expression in colorectal cancer: relevance of different isoforms for tumor progression and patient survival.

Metallothioneins are a family of small, cysteine-rich proteins with many functions. Immunohistochemical evaluation of all metallothionein 1 + 2 isoforms in colorectal tumors has demonstrated an important down-regulation compared with normal tissue, although its prognostic significance is unclear. Moreover, the contribution of individual isoforms to overall metallothionein down-regulation is not known. To address these important issues, we analyzed the messenger RNA expression levels of all functional metallothionein 1 + 2 isoforms by quantitative reverse transcription polymerase chain reaction in 22 pairs of normal and tumor-microdissected epithelia and correlated these to the overall immunohistochemical protein expression. Our results showed that 5 isoforms (MT1G, 1E, 1F, 1H, and 1M) were lost during the transition from normal mucosa to tumor, whereas MT1X and MT2A were less down-regulated, and their expression was correlated with overall protein positivity. Second, we showed that MT1G hypermethylation occurred in cell lines and in 29% of tumor samples, whereas histone deacetylase inhibitors are able to induce most isoforms. Furthermore, we analyzed by immunohistochemistry 107 normal mucosae, 25 adenomas, 81 carcinomas, and 19 lymph node metastases to evaluate metallothionein expression during different stages of cancer development and to assess its relationship to patient survival. A lower immunohistochemical expression was associated with poorer survival, although it was not an independent predictor. Overall, this study identifies for the first time the relevant metallothionein isoforms for colorectal cancer progression, supports the concept that their loss is associated with worse prognosis, and suggests 2 mechanisms for epigenetic repression of metallothionein expression in colorectal tumors.