ABCG2 Expression as a Potential Survival Predictor in Human Gliomas.

Gliomas are notably challenging to treat due to their invasive nature and resistance to conventional therapies. The ABCG2 protein has attracted attention for its role in multidrug resistance, complicating treatment effectiveness. This study scrutinized the relationship between ABCG2 expression and glioma grade and the role of ABCG2 in the process of glioma progression, aiming to evaluate ABCG2 expression as a predictive factor of tumor progression and patient survival. Conducted at Dubrava University Hospital, Zagreb, Croatia, the study analyzed 152 glioma specimens from 2013 to 2022, assessing ABCG2 expression alongside standard clinical markers. A significant association was found between patients' survival and the ABCG2 profile (p = 0.003, r = 0.24), separately for patients who underwent chemotherapy (p = 0.0004, r = 0.32) and radiotherapy (p = 0.003, r = 0.29). Furthermore, the ABCG2 profile was significantly associated with disease progression (p = 0.007, r = 0.23), tumor grade (p = 0.0002, r = 0.31), and Ki67 expression (p = 0.0004, r = 0.31). ABCG2-positive tumor cells only showed association with Ki67 expression (p = 0.002, r = 0.28). The ABCG2 profile was found to affect the overall patient survival (p = 0.02) and represent a moderate indicator of tumor progression (p = 0.01), unlike the percentage of ABCG2-positive tumor cells. ABCG2 may serve as a marker of angiogenesis and vascular abnormalities within tumors, predicting glioma progression and treatment response. Targeting ABCG2 could enhance chemoradiotherapy efficacy and improve patient outcomes, which highlights its value in assessing tumor aggressiveness and designing treatment strategies.

Brain metastases of the mucoepidermoid lung carcinoma: a case report.

Mucoepidermoid carcinoma, a salivary gland tumor, rarely occurs in bronchial mucous glands. Brain metastases are rarely seen which makes for a challenging diagnosis and treatment approach. A 40-year-old woman presented with confusion, and ataxia, accompanied by a declining Glasgow Coma Score. Brain computerized tomography revealed two hyperdense, postcontrast-enhanced infra- and supratentorial lesions with perifocal edema. First causing obstructive hydrocephalus. The initial surgery involved external ventricular drainage system placement leading to the patient's clinical improvement. After radiological diagnostics, both lesions were resected without complications. Histopathological analysis revealed solid clusters of atypical, polygonal epithelial cells exhibiting mucin production, classified as a poorly differentiated mucoepidermoid carcinoma metastasis which originated from the upper lobe's apicoposterior segment and left lung. The correct treatment approach remains elusive due to the infrequent occurrence and challenging diagnosis. While new oncological and radiosurgery options promise improved overall survival rates, radical resection remains the preferred initial option.

Merkel Cell Carcinoma of Unknown Primary Origin.

Merkel cell carcinoma (MCC) is a rare and highly aggressive primary cutaneous neuroendocrine carcinoma most often occurring in the elderly. Risk factors include chronic sun exposure and immunosuppression (1). MCC is associated with frequent recurrences and a high metastatic potential and mortality rate (1). It is the second most common cause of skin-cancer-related death after melanoma. At primary diagnosis with an apparent cutaneous tumor, loco-regional metastases are present in up to 30% of patients, and 6-12% have distant metastatic disease (2-3). Up to 5% of cases present with unknown primary origin (4). Five-year overall survival for patients with advanced or metastatic disease is 13-18% (4). We report two cases of MCC presenting without primary cutaneous involvement; first at an unusual location in the adipose tissue of the right breast, and the second one with only a clinically positive left inguinal lymph node. In October 2018, a 78-year-old woman presented with a 15-week history of a painless solitary mass in the upper outer quadrant (UOQ) of the right breast with no visible cutaneous involvement. Her medical history included hypertension, dyslipidemia, and plaque psoriasis. She underwent ultrasound guided biopsy, and histopathology confirmed the diagnosis of metastatic MCC (mMCC). Positron emission tomography/computed tomography (PET/CT) scans showed increased standardized uptake values in the mass in the UOQ and an additional mass in the lower inner quadrant (Figure 1A). The patient underwent mastectomy and lymph node dissection of the right axilla. Histopathology confirmed mMCC and negative axillary lymph nodes. Regular follow-up (clinical examination, PET/CT scan, ultrasound, mammography) every 6 months revealed no disease recurrence during this 4-year period (Figure 1B). In September 2021, a 66-year-old man was referred to our Clinic with clinically detectable painful left inguinal lymphadenopathy. Excisional biopsy was performed, and histopathology confirmed the diagnosis of mMCC (Figure 2). After an extensive clinical and imaging evaluation (PET/CT scan), which confirmed disseminated disease (Figure 3A), initial treatment with the programmed cell death ligand 1 inhibitor (anti PD-L1) avelumab was proposed. The first cycle consisting of seven intravenous applications, and was applied in October 2021. After one year and completion of the third cycle of therapy, imaging assessment (PET-CT scan) detected a solitary lesion in the pancreas. Fine needle aspiration biopsy confirmed a distant metastasis of MCC that was later treated with stereotactic radiosurgery. The fourth cycle of immunotherapy was completed in March 2023. No treatment-related adverse events were noted during these 18 months of follow-up. Recent PET/CT scans demonstrated scaring tissue in the pancreas with no signs of locoregional or distant metastatic disease (Figure 3B). Management of MCC should be individualized based on the specific pattern of disease presentation. The presence of nodal disease is one of the most powerful predictors of overall survival and risk for developing distant metastatic disease (3-4). Multidisciplinary tumor board discussions are mandatory for the management of advanced MCC. New emerging treatment options have once again returned focus to this rare and highly-aggressive entity. Until recent years, mMCC was managed with extensive surgery, radiotherapy, or chemotherapy, but responses were not durable (1). Based on new clinical trials, immunotherapy has now become a rational and promising treatment option and is considered as first-line treatment in patients with advanced MCC (5). The management of patients with MCC of unknown primary origin should adhere to that for patients with an identifiable primary tumour (6). Although cutaneous manifestations are the hallmark of MCC, only a minority of cases have been reported in the literature without any cutaneous involvement (7-10). Our cases highlight this unusual presentation of MCC that could be misleading and contribute to delayed diagnosis. We therefore emphasize the importance of considering rare forms of malignancies such as MCC even in the absence of a primary cutaneous lesion.