Validation of an NGS Panel Designed for Detection of Actionable Mutations in Tumors Common in Latin America.

Next-generation sequencing (NGS) is progressively being used in clinical practice. However, several barriers preclude using this technology for precision oncology in most Latin American countries. To overcome some of these barriers, we have designed a 25-gene panel that contains predictive biomarkers for most current and near-future available therapies in Chile and Latin America. Library preparation was optimized to account for low DNA integrity observed in formalin-fixed paraffin-embedded tissue. The workflow includes an automated bioinformatic pipeline that accounts for the underrepresentation of Latin Americans in genome databases. The panel detected small insertions, deletions, and single nucleotide variants down to allelic frequencies of 0.05 with high sensitivity, specificity, and reproducibility. The workflow was validated in 272 clinical samples from several solid tumor types, including gallbladder (GBC). More than 50 biomarkers were detected in these samples, mainly in BRCA1/2, KRAS, and PIK3CA genes. In GBC, biomarkers for PARP, EGFR, PIK3CA, mTOR, and Hedgehog signaling inhibitors were found. Thus, this small NGS panel is an accurate and sensitive method that may constitute a more cost-efficient alternative to multiple non-NGS assays and costly, large NGS panels. This kind of streamlined assay with automated bioinformatics analysis may facilitate the implementation of precision medicine in Latin America.

Upper thoracic dumbbell-shaped tumor resected in one stage posterior approach: case report.

Upper thoracic tumors may develop spinal cord compression. By surgery at the time of diagnosis, a neurological deficit can be avoided. However, this particular localization requires a double approach to decompress the spinal cord and thoracic structures. The posterior extracavitary approach results in resection of the spinal canal, the foraminal component, and the extraspinal fragment, but is not routinely used by most neurosurgeons. A 56-year-old woman with a two-month history of axial thoracic pain and cough. The patient has a normal neurological examination. Thoracic computed tomography (CT) scan with contrast agent was performed, evincing a dumbbell-shaped tumor on the left T3-T4. Magnetic resonance imaging (MRI) confirms the diagnosis, showing a 4 cm diameter tumor that compresses the spinal cord without myelopathy. The surgery was performed posteriorly, with costotransversectomy, allowing complete resection under intraoperative neurophysiological monitoring. The patient developed no thoracic or neurological complications. One-stage posterior approach is possible and effective during the treatment of the upper thoracic dumbbell-shaped tumors, avoiding a change in surgical position, thoracic morbidity, and dependence on assisting surgeons.

Acinic cell carcinoma of the parotid gland: a case report and review of the literature.

We report on a patient who was referred to the ENT service following an incidental finding on an MRI scan of the brain. It revealed a mass in the right parapharyngeal space, and additional imaging confirmed the presence of a solid cystic expansive mass with moderate enhancement following contrast media injection. The patient was treated with a total parotidectomy followed by radiotherapy. Currently, the patient is disease-free without any complications.

Giant undifferentiated oropharyngeal sarcoma: a case report and review of the literature.

We report on a patient who presented to the Ear, Nose and Throat (ENT) clinic with swelling of the neck, dysphagia, headache, dyspnea and stridor. Imaging studies revealed an expansive heterogeneous process to the left retropharyngeal region. The mass was ovoid in shape, displaying moderate enhancement after intravenous contrast administration. Subsequently, a biopsy revealed the presence of undifferentiated sarcoma. The patient was treated with chemotherapy followed by radiation therapy, but follow-up exams at 6 months posttreatment revealed that while the tumor was stable, it persisted. Consequently, the patient was enrolled in a palliative care and pain control program and is currently being followed.

Mandibular central mucoepidermoid carcinoma: a case report and review of the literature.

We report the case of a patient whose main complaint was swelling on the right side of the mandible when he presented to the Ear, Nose and Throat (ENT) Service. Imaging studies revealed a large homogeneous, multilocular, expansive lesion in the body of the right mandibular ramus. The lesion was poorly enhanced following intravenous contrast injection. The patient was treated with hemimandibular surgical resection, fibula free flap reconstruction and adjuvant radiotherapy. Currently, the patient is disease free and free of posttreatment complications.

Orbito-ethmoidal rhabdomyosarcoma in an adult patient: a case report and review of the literature.

We report a patient who presented to the ENT service complaining of nasal obstruction, exophthalmos, edema and ipsilateral facial congestion. Imaging studies revealed an aggressive noncalcified solid mass centered in the left nasoethmoidal region and heterogeneous avid enhancement following contrast media injection. Subsequently, a biopsy confirmed the presence of solid alveolar rhabdomyosarcoma. The patient was treated with chemoradiation therapy for 7 weeks. Due to the advanced stage of the disease, the patient was enrolled in a palliative care and pain control program.

Oncocytoma of the parotid gland: a case report and review of the literature.

We report the case of a patient who presented to the ENT service with left facial swelling of 5 months duration. Imaging studies revealed a dense expansive mass confined to the inside of the left deep parotid lobule and moderate enhancement following contrast media injection. Subsequently, a biopsy confirmed the presence of an oncocytoma. The patient was treated with total parotidectomy, complete tumor resection and sparing facial nerve surgery. Today, the patient is disease free and has no complications.

Skull base clear cell carcinoma, metastasis of renal primary tumor: a case report and literature review.

We report on a patient who presented with cranial nerve VI bilateral paresis, absence of pharyngeal reflex, dysarthria, right tongue deviation, and right facial paralysis. Imaging studies showed an expansive process in the cranial base with clivus and petrous apex osteolysis. A biopsy confirmed the presence of clear cell adenocarcinoma and suspicion of renal tumor metastases. Abdominal imaging studies revealed a mass in the right kidney. Consequently, radiotherapy was performed, and the patient was enrolled in a palliative care and pain control program.

Epithelial expression of p53, mdm-2 and p21 in normal lip and actinic cheilitis.

The p53 pathway is commonly altered during oral and skin carcinogenesis. The lip is a transition tissue between skin and oral mucosa, which in response to UVB exposure also exhibits alterations in the expression of p53 and p53-related genes that could lead to malignant transformation. To assess if the p53-regulated proteins murine-double-minute (mdm)-2 and p21 are altered during early lip carcinogenesis, biopsies from normal lip (n=16) and the premalignant lip lesion, actinic cheilitis (AC) (n=26) were processed for the immunohistochemical detection of p53, p21 and mdm-2 in serial co-localized sections. Epithelial co-expression of p53 and mdm-2 was significantly increased in AC as compared to normal lip (P<0.001). No differences in epithelial p21 expression were found between normal lip and AC. While in normal lip mdm-2 and p21 were significantly correlated with p53, in AC only mdm-2 was associated with p53 expression. Multivariate logistic regression analysis of the three markers (Wald stepwise) showed that p53 is the only predictor of AC. The results point to alterations in the p53 pathway during early lip carcinogenesis, highlighting p53 as a potential marker of early malignancy of the lip.

Sinonasal acinic cell carcinoma: a clinicopathologic study of four cases.

BACKGROUND: Acinic cell carcinoma is a low-grade malignant epithelial salivary gland neoplasm with a predilection for the parotid gland. To date, only 11 cases of sinonasal acinic cell carcinomas have been reported in the English-language literature. We present the clinicopathologic features of four sinonasal acinic cell carcinomas. METHODS: The demographic data and pathologic material of four patients with sinonasal acinic cell carcinoma identified from the files of the Department of Pathology at The University of Texas M. D. Anderson Cancer Center between 1984 and 2002 were reviewed. RESULTS: The four patients were two men and two women, with an age range of 42 to 65 years (mean, 54 years). The patients were initially seen with unilateral nasal obstruction. Histologically, all tumors were composed of round to ovoid cells with clear and/or basophilic granular cytoplasm and round, hyperchromatic, small, eccentrically located nuclei. The growth pattern was lobular, solid, and follicular. Histochemically, periodic acid-Schiff diastase-resistant granules were demonstrated in all cases. All patients were treated surgically. In addition, one patient received postoperative radiation. All patients are alive and well, with follow-up from 4 to 17 years. CONCLUSIONS: Sinonasal acinic cell carcinoma is a distinct low-grade carcinoma that can be distinguished from other neoplasms by light microscopy and histochemical staining methods. Pathologists and surgeons should be aware of the occurrence of this type of salivary gland neoplasm in the sinonasal tract.

Intracranial extension of acinic cell carcinoma of the parotid gland.

We report the case of a 47-year-old woman who experienced multiple recurrences of acinic cell carcinoma, lung metastasis, and intracranial extension of the tumor during a 32-year period. In this report, the clinical, microscopic, histochemical, and electron microscopy features of this acinic cell carcinoma are described, and a review of published information about this neoplasm is presented.

Inhibition of mammalian target of rapamycin reverses alveolar epithelial neoplasia induced by oncogenic K-ras.

The serine/threonine kinase AKT and its downstream mediator mammalian target of rapamycin (mTOR) are activated in lung adenocarcinoma, and clinical trials are under way to test whether inhibition of mTOR is useful in treating lung cancer. Here, we report that mTOR inhibition blocked malignant progression in K-ras(LA1) mice, which undergo somatic activation of the K-ras oncogene and display morphologic changes in alveolar epithelial cells that recapitulate those of precursors of human lung adenocarcinoma. Levels of phospho-S6(Ser236/235), a downstream mediator of mTOR, increased with malignant progression (normal alveolar epithelial cells to adenocarcinoma) in K-ras(LA1) mice and in patients with lung adenocarcinoma. Atypical alveolar hyperplasia, an early neoplastic change, was prominently associated with macrophages and expressed high levels of phospho-S6(Ser236/235). mTOR inhibition in K-ras(LA1) mice by treatment with the rapamycin analogue CCI-779 reduced the size and number of early epithelial neoplastic lesions (atypical alveolar hyperplasia and adenomas) and induced apoptosis of intraepithelial macrophages. LKR-13, a lung adenocarcinoma cell line derived from K-ras(LA1) mice, was resistant to treatment with CCI-779 in vitro. However, LKR-13 cells grown as syngeneic tumors recruited macrophages, and those tumors regressed in response to treatment with CCI-779. Lastly, conditioned medium from primary cultures of alveolar macrophages stimulated the proliferation of LKR-13 cells. These findings provide evidence that the expansion of lung adenocarcinoma precursors induced by oncogenic K-ras requires mTOR-dependent signaling and that host factors derived from macrophages play a critical role in adenocarcinoma progression.

Elevated expression of p21 (WAF1/Cip1) in hormonally active pituitary adenomas.

Although most pituitary adenomas arise sporadically, molecular studies show alterations of known oncogenes and/or tumor suppressor genes in a small percentage of adenomas, and the molecular pathology of most is unknown. The p21 gene is a universal inhibitor of cyclin-dependent kinases and serves as a cell-cycle blocker and cell-growth inhibitor. Pituitary adenomas (n = 54) were immunophenotyped for hormone production (prolactin, growth hormone, adrenocorticotropin, thyrotropin, follicle-stimulating hormone, and luteinizing hormone), and expression of p21 was determined by immunohistochemistry. The percentage of cells expressing p21 for each tumor was evaluated blindly with regard to hormone status, and expression of p21 was then correlated with the results of hormone immunotyping. Results show a striking difference in the expression of p21 between immunonegative adenomas and hormone-producing tumors. Whereas 71% (10/14) of nonfunctional adenomas exhibit p21 expression in fewer than 5% of cells, 77% (31/40) of hormone-producing adenomas show expression in more than 25% of cells, and of these, 68% (21/31) show expression in more than 75% of cells. Overexpression of p21 is particularly striking for growth hormone-producing tumors, of which 92% (11/12) show expression in more than 75% of cells. Hormone-producing pituitary adenomas express much more p21 than do immunonegative adenomas. These high levels of p21 expression represent the most widespread molecular genetic alteration demonstrated to date in pituitary adenomas.