Role of 18F-FDG PET/CT in evaluating molecular subtypes and clinicopathological features of primary breast cancer.

OBJECTIVE: In this study, primary tumors' fluorine-18-fluorodeoxyglucose (F-FDG) uptake in luminal A, luminal B, triple-negative, and human epidermal growth factor receptor type-2 subtypes of breast cancer was evaluated. In addition, the relationship between the primary tumor maximum standardized uptake value (SUVmax) value and the presence of distant metastasis and axillary involvement was evaluated. PATIENTS AND METHODS: Whole-body F-FDG PET/computed tomography (CT) imaging of 493 patients (mean age; 54.6±13.2 years) diagnosed with primary breast cancer were analyzed retrospectively. PET/CT imaging was obtained 60 min after the intravenous administration of F-FDG. F-FDG uptake of the lesions was assessed by calculating the SUVmax. Histopathological analyses were carried out on the basis of biopsy samples before PET/CT. For histopathological staging, the Scarff Bloom Richardson classification system was utilized, and patients were classified into luminal A, luminal B, triple-negative, and human epidermal growth factor receptor type-2 molecular subtypes. RESULTS: 82.9% of the patients had invasive ductal carcinoma, 5.8% had invasive lobular carcinoma, 4.2% had apocrine carcinoma, 3.8% had mucinous carcinoma, and 3.4% has mixed carcinoma. Although the highest mean SUVmax was calculated in apocrine tumors (12.4±7.2), the lowest mean SUVmax was calculated in lobular carcinoma (6.8±4.6), and a statistically significant difference was found between the histological groups (P<0.001). F-FDG uptake was reported to be significantly higher in the triple-negative subtype than the luminal types, and in the luminal B subtype than the luminal A subtype. A statistically significant relation was found between primary tumor SUVmax and distant nodal, organ metastasis (P=0.003 and <0.001, respectively). CONCLUSION: Increased primary tumor F-FDG uptake was associated with aggressive molecular subtypes in this study. The relationship of distant nodal and organ metastasis with primary tumor SUVmax showed that increased F-FDG uptake is important in terms of management of therapy and prognosis.

LKB1 mutations and their correlation with LKB1 and Rheb expression in bladder cancer.

Although there are extensive studies on the genetics of bladder cancer, several questions remain unanswered. One of the pathways which are altered in bladder cancer is the mTOR signaling pathway. In the present study, we analyzed the expression of Rheb gene and genetic alterations in the LKB1 gene which are the key components of mTOR pathway. Nine exons of the LKB1 gene were analyzed by direct sequencing in 51 bladder cancer patients. To investigate the expression of Rheb and LKB1, real-time quantitative RT-PCR was performed in bladder tumor and normal bladder tissue samples. We did not observed a statistically significant difference in Rheb or LKB1 expression between the tumor and normal tissue samples. We detected a novel missense mutation creating stop codon in a high percent of the tumor samples. Five different single nucleotide substitutions were also observed in the introns. Our results indicate that LKB1 gene may play a role in the progression of bladder cancer.

Vaginal Schwannoma in a case with uterine myoma.

Only 1% of gynecological neoplasms are vaginal, and mesenchymal tumors constitute only 2% of vaginal neoplasms. The most common form is leiomyomas. Schwannomas arise from the peripheral nerve sheath. We report a case of vaginal schwannoma associated with uterine myoma. A 52-year-old woman presented with lower abdominal pain and menorrhagia for a duration of 6 months. At sonographic examination, the patient was found to have uterine myomas and a solid mass measuring 5x4.5 cm beneath the vaginal wall. At laparotomy, the uterus with myoma was removed using our standard operation procedures. Surgical excision of the mass from vaginal aspect was also undertaken, and the histology demonstrated schwannoma. The tumor cells were vimentin (+), desmin (-), smooth muscle alpha-actin (-), HMB-45 (-), MART-1 (-) and S-100 (+). There is no evidence of recurrence during 6 months follow-up. The differential diagnosis of a mass in the vagina includes also schwannomas. Immunocytochemical labeling of the tumor cells is essential. Simple resection of the mass is the preferred method of treatment.