Factors determining whether diffuse large B-cell lymphoma samples are detected by flow cytometry.

INTRODUCTION: Flow cytometry (FCM) is widely used in the diagnosis of mature B-cell neoplasms (MBN), and FCM data are usually consistent with morphological findings. However, diffuse large B-cell lymphoma (DLBCL), a common MBN, is sometimes not detected by FCM. This study aimed to explore factors that increase the likelihood of failure to detect DLBCL by FCM. METHODS: Cases with a final diagnosis of DLBCL that were analysed by eight-colour FCM were retrospectively collated. Clinical, FCM, histopathological and genetic data were compared between cases detected and cases not detected by FCM. RESULTS: DLBCL cases from 135 different patients were analysed, of which 22 (16%) were not detected by FCM. In samples not detected by flow cytometry, lymphocytes were a lower percentage of total events (p = 0.02), and T cells were a higher percentage of total lymphocytes (p = 0.01). Cases with high MYC protein expression on immunohistochemistry were less likely to be missed by FCM (p = 0.011). Detection of DLBCL was not different between germinal centre B-cell (GCB) and non-GCB subtypes, not significantly affected by the presence of necrosis or fibrosis, and not significantly different between biopsy specimens compared to fine-needle aspirates, or between samples from nodal compared to extranodal tissue. CONCLUSION: The study identifies several factors which affect the likelihood of DLBCL being missed by FCM. Even with eight-colour analysis, FCM fails to detect numerous cases of DLBCL.

Twice Bitten, Thrice Shy: A Case of Recurrent Isolated Cardiac Sarcoidosis in the Transplanted Heart.

We present a case of recurrent isolated cardiac sarcoidosis, 3 years post-heart transplantation. The case highlights the scarcity of data on the utility of immunosuppression in cardiac sarcoidosis and, in particular, raises questions about the optimal immunosuppression regimen in transplant recipients. (Level of Difficulty: Advanced.).

MTOR signaling orchestrates stress-induced mutagenesis, facilitating adaptive evolution in cancer.

In microorganisms, evolutionarily conserved mechanisms facilitate adaptation to harsh conditions through stress-induced mutagenesis (SIM). Analogous processes may underpin progression and therapeutic failure in human cancer. We describe SIM in multiple in vitro and in vivo models of human cancers under nongenotoxic drug selection, paradoxically enhancing adaptation at a competing intrinsic fitness cost. A genome-wide approach identified the mechanistic target of rapamycin (MTOR) as a stress-sensing rheostat mediating SIM across multiple cancer types and conditions. These observations are consistent with a two-phase model for drug resistance, in which an initially rapid expansion of genetic diversity is counterbalanced by an intrinsic fitness penalty, subsequently normalizing to complete adaptation under the new conditions. This model suggests synthetic lethal strategies to minimize resistance to anticancer therapy.

Neuromuscular and vascular hamartoma as an unusual cause of small bowel obstruction.

INTRODUCTION: Neuromuscular and vascular hamartoma (NMVH) is a rare, controversial lesion of the intestine, with only 23 cases reported in the English literature since its initial description in 1982. PRESENTATION OF CASE: A 59year old female suffering from longstanding Crohn's disease with chronic stricture presented with symptoms of small bowel obstruction. Contrast studies demonstrated massive dilatation of the proximal small bowel. Laparotomy identified a 5cm long stenotic segment of ileum, with grossly distended jejunum and ileum proximally. Pathology determined the stricture's aetiology as a neuromuscular and vascular hamartoma of the small intestine. DISCUSSION: NMVH is a benign lesion of hamartomatous origin. Its very existence is questionable due to histological similarities with several reactive pathologies, such as Crohn's and diaphragm diseases. CONCLUSION: NMVH could be confused with a spectrum of chronic inflammatory bowel conditions, but this report establishes it as a distinct cause of chronic bowel obstruction.

PI3K pathway activation in breast cancer is associated with the basal-like phenotype and cancer-specific mortality.

Breast cancer is a common malignancy with current biological therapies tailored to steroid hormone (ER, PR) and HER2 receptor status. Understanding the biological basis of resistance to current targeted therapies and the identification of new potential therapeutic targets is an ongoing challenge. The PI3K pathway is altered in a high proportion of breast cancers and may contribute to therapeutic resistance. We undertook an integrative study of mutational, copy number and expression analyses of key regulators of the PI3K pathway in a cohort of 292 invasive breast cancer patients with known treatment outcomes. The alterations identified in this cohort included PIK3CA mutations (12/168, i.e. 7%), PIK3CA copy number gain (28/209, i.e. 14%), PTEN loss (73/258, i.e. 28%) and AKT activation (62/258, i.e. 24%). Overall at least 1 parameter was altered in 72% (139/193) of primary breast cancers. PI3K pathway activation was significantly associated with ER negative (p = 0.0008) and PR negative (p = 0.006) status, high tumor grade (p = 0.032) and a "basal-like" phenotype (p = 0.01), where 92% (25/27) of tumors had an altered pathway. In univariate analysis, PI3K pathway aberrations were associated with death from breast cancer; however, this relationship was not maintained in multivariate analysis. No association was identified between an activated pathway and outcome in tamoxifen- or chemotherapy-treated patients. We concluded that >70% of breast cancers have an alteration in at least 1 component of the PI3K pathway and this might be exploited to therapeutic advantage especially in "basal-like" cancers.