Assessment of the quality of DNA from various formalin-fixed paraffin-embedded (FFPE) tissues and the use of this DNA for next-generation sequencing (NGS) with no artifactual mutation.

Formalin-fixed, paraffin-embedded (FFPE) tissues used for pathological diagnosis are valuable for studying cancer genomics. In particular, laser-capture microdissection of target cells determined by histopathology combined with FFPE tissue section immunohistochemistry (IHC) enables precise analysis by next-generation sequencing (NGS) of the genetic events occurring in cancer. The result is a new strategy for a pathological tool for cancer diagnosis: 'microgenomics'. To more conveniently and precisely perform microgenomics, we revealed by systematic analysis the following three details regarding FFPE DNA compared with paired frozen tissue DNA. 1) The best quality of FFPE DNA is obtained by tissue fixation with 10% neutral buffered formalin for 1 day and heat treatment of tissue lysates at 95°C for 30 minutes. 2) IHC staining of FFPE tissues decreases the quantity and quality of FFPE DNA to one-fourth, and antigen retrieval (at 120°C for 15 minutes, pH 6.0) is the major reason for this decrease. 3) FFPE DNA prepared as described herein is sufficient for NGS. For non-mutated tissue specimens, no artifactual mutation occurs during FFPE preparation, as shown by precise comparison of NGS of FFPE DNA and paired frozen tissue DNA followed by validation. These results demonstrate that even FFPE tissues used for routine clinical diagnosis can be utilized to obtain reliable NGS data if appropriate conditions of fixation and validation are applied.

p62 Regulates the Proliferation of Molecular Apocrine Breast Cancer Cells.

p62, also called sequestosome 1 (SQSTM1), is a multifunctional signaling molecule that affects cell proliferation. Recently, we found accumulation of p62 in apocrine carcinoma of the breast, however, the biological role of p62 expression in apocrine carcinoma still remains unclear. To investigate whether p62 might contribute to tumor cell proliferation in apocrine carcinomas, we used the MDA-MB-453 (androgen receptor-positive, HER2-type) and MFM223 (androgen receptor-positive, triple-negative type) breast cancer cell lines as models of molecular apocrine carcinoma. Both MDA-MB-453 and MFM223 showed strong and d high p62 protein expression than MCF7 cells (androgen receptor-negative, luminal A type). Knockdown of p62 resulted in significant reduction of the cell proliferative activity in both MDA-MB-453 (P<0.01) and MFM223 (P<0.05). In conclusion, p62 could contribute to cell proliferation and represent a therapeutic target in apocrine carcinoma.

Retroperitoneal Hematoma in a Patient with Advanced Chronic Kidney Disease Receiving Warfarin Therapy.

A 73-year-old man with chronic kidney disease stage G5 was admitted to our hospital because of a worsening kidney dysfunction. He had undergone prosthetic valve replacement of the mitral valve 5 years previously and was currently taking warfarin. He showed excessive anticoagulation on admission, with a prothrombin time-international normalized ratio (PT-INR) of 3.91. The use of warfarin was ceased and PT-INR decreased to 2.1. Since the patient would need renal replacement therapy, he underwent arteriovenous fistula surgery for hemodialysis access on day 16. However, on day 18, he suddenly complained of lumbago and went into shock. His blood pressure dropped to 73/49 mmHg, and the hemoglobin level fell to 4.9 g/dL. Computed tomography revealed a huge retroperitoneal hematoma. Emergent lumbar artery embolization was performed on two consecutive days; however, the bleeding persisted, with subsequent development of abdominal compartment syndrome with impaired respiratory and cardiovascular function, and the patient died. Autopsy revealed a hematoma measuring 30×20×20 cm involving the psoas muscle and external iliac artery; the hematoma was covered with fibrous tissue instead of muscle. The psoas muscle is supplied by the internal iliac artery; however, a collapsed artery could not be confirmed in our patient. The closest major artery to the hematoma was located at the intersection of the psoas muscle and the external iliac artery. All arteries showed severe atherosclerosis. In patients with advanced chronic kidney disease, anticoagulant therapy should be administered carefully, and the etiology of retroperitoneal hematoma should be further investigated.

Overexpression of PGC1α and accumulation of p62 in apocrine carcinoma of the breast.

Apocrine carcinoma is categorized as a special type of breast carcinoma because of its specific morphological features. To clarify the characteristics of apocrine carcinoma from the point of view of the mitochondrial profile, we conducted a comparative study between apocrine and non-apocrine carcinomas. The expressions of mitochondrial related factors (PGC1α, Nrf1, Nrf2, mtTFA and COX4) were examined in a testing set of breast cancer tissue. Apocrine carcinomas showed a clear tendency towards higher mRNA expression levels of PGC1α than non-apocrine carcinomas. The expression of the selected factor, PGC1α, as well as that of p62 was further examined. The results revealed that apocrine carcinomas showed a higher immunohistochemical positivity rate for PGC1α (21.3% vs. 3.2%; P = 0.008), and that the mRNA expression level of PGC1α was significantly higher in apocrine carcinoma than in non-apocrine carcinoma (P = 0.007). The immunohistochemical positivity rate for p62 protein was also higher in apocrine carcinomas (44.7% vs. 21.0%; P = 0.015), although no significant difference in the p62 mRNA expression level was detected between the two types of carcinoma (P = 0.633). In conclusion, this study revealed that apocrine carcinoma overexpressed PGC1α contributing to mitochondrial biogenesis, and also p62 protein accumulation.

Clinicopathological characteristics of anaplastic carcinoma of the pancreas with rhabdoid features.

Undifferentiated (anaplastic) carcinoma with rhabdoid features is a rare and aggressive subtype of pancreatic carcinoma. Here, we report the clinical, histological, and immunohistochemical phenotypes in six autopsy cases of anaplastic carcinoma with rhabdoid features. The patients ranged between 44 and 76 years of age (median, 61 years) and consisted of four males and two females. All patients except one case died within 3 months of diagnosis, as these tumors were found at an advanced stage and were chemoresistant. At autopsy, tumor masses measuring 4-22 cm in maximum diameter were mainly located in the pancreatic body and tail. Microscopically, all cases showed anaplastic carcinoma with rhabdoid features that were discohesive with round to polygonal eosinophilic cytoplasm with occasional inclusions, and that had vesicular nuclei, and prominent nucleoli. Immunohistochemistry showed that the rhabdoid cells, particularly the inclusions, were strongly positive for pan-cytokeratin (AE1/AE3) and vimentin. Meanwhile, downregulation or aberrant cytoplasmic localization with focal aggregation of E-cadherin, ß-catenin, and EMA were frequently observed in the rhabdoid cells. Moreover, the intracytoplasmic inclusions were labeled with selective autophagy-related molecules including p62/SQSTM1, ubiquitin, and kelch-like ECH-associated protein 1 (KEAP1). In addition, nuclear factor erythroid 2-related factor 2 (NRF2) and overexpression of its target molecule multidrug resistance-associated protein 1 (MRP1) were commonly observed in the rhabdoid cells. Therefore, these results suggest that p62-mediated aggregation of ubiquitinated intermediate filaments and membranous proteins is an important phenomenon in the rhabdoid phenotype. Indeed, the ubiquitinated aggregates of p62 and KEAP1 would induce activation of NRF2 and upregulation of MRP1, leading to potential chemoresistance of anaplastic carcinoma with rhabdoid features.

Well-differentiated papillary mesothelioma, possibly giving rise to diffuse malignant mesothelioma: a case report.

Well-differentiated papillary mesothelioma (WDPM) is a distinct subtype of mesothelial tumor from diffuse malignant mesothelioma (DMM), with an uncertain malignant potential. The relationship between WDPM and DMM, with regard to the ability of the former to develop into the latter, is also unknown. A 58-year-old woman, diagnosed with a rectal carcinoid tumor, underwent removal of the lymph nodes via the abdomen in 2004. A large number of white miliary nodules were identified on the mesentery and peritoneum, which were histologically diagnosed as WDPM. No further therapy was administered, but the patient was followed-up using imaging methods. Seven years later, an abdominal wall mass was discovered using positron emission tomography-computed tomography, and a laparotomy biopsy was performed. DMM was diagnosed, because mesothelioma with extended invasion had been histologically identified. Mesothelioma similar to papillary proliferation was present on the outer layer of the peritoneum, and an infiltrating lesion with continuous restiform or solid-like structures was noted. WDPM was believed to have undergone malignant transformation. Compared to DMM, WDPM has a good prognosis and is considered a benign or borderline neoplasm. Our findings suggest that WDPM does have malignant potential, however, because histological findings indicated a malignant transformation of WDPM to DMM.