Objective: To investigate whether underlying medical conditions contribute to the fatigue and high incidence of infections that can occur during repeated intense training. Method: Forty one competitive athletes (22 male, 19 female) with persistent fatigue and/or recurrent infections associated with performance decrements had a thorough medical examination and a series of clinical investigations to identify potential medical causes. Results: Conditions with the potential to cause fatigue and/or recurrent infections were identified in 68% of the athletes. The most common were partial humoral immune deficiency (28%) and unresolved viral infections (27%). Non-fasting hypoglycaemia was common (28%). Other conditions included allergic disease (15%), new or poorly controlled asthma (13%), upper airway dysfunction (5%), sleep disorders (15%), iron depletion (3%), and one case of a thyroid disorder. A positive antinuclear antibody was detected in 21% of the athletes, without any clinical evidence of autoimmune disorders. Evidence of Epstein-Barr virus reactivation was detected in 22% of the athletes tested. Conclusions: Athletes with recurrent infections, fatigue, and associated poor performance may benefit from a thorough investigation of potentially reversible underlying medical conditions, especially when these conditions cause disruption to training and competition. Unresolved viral infections are not routinely assessed in elite athletes, but it may be worth considering in those experiencing fatigue and performing poorly.

Invasive lobular carcinoma (ILC) accounts for 10% to 15% of breast cancers in the United States, 80% of which are estrogen receptor (ER)-positive, with an unusual metastatic pattern of spread to sites such as the serosa, meninges, and ovaries, among others. Lobular cancer presents significant challenges in detection and clinical management given its multifocality and multicentricity at presentation. Despite the unique features of ILC, it is often lumped with hormone receptor-positive invasive ductal cancers (IDC); consequently, ILC screening, treatment, and follow-up strategies are largely based on data from IDC. Despite both being treated as ERpositive breast cancer, querying the Cancer Genome Atlas database shows distinctive molecular aberrations in ILC compared with IDC, such as E-cadherin loss (66% vs. 3%), FOXA1 mutations (7% vs. 2%), and GATA3 mutations (5% vs. 20%).Moreover, compared with patients with IDC, patients with ILC are less likely to undergo breast-conserving surgery, with lower rates of complete response following therapy as these tumors are less chemosensitive. Taken together, this suggests that ILC is biologically distinct, which may influence tumorigenesis and therapeutic strategies. Long-term survival and clinical outcomes in patients with ILC are worse than in stage-and grade-matched patients with IDC; therefore, nuanced criteria are needed to better define treatment goals and protocols tailored to ILC's unique biology. This comprehensive review highlights the histologic and clinicopathologic features that distinguish ILC from IDC, with an in-depth discussion of ILC's molecular alterations and biomarkers, clinical trials and treatment strategies, and future targets for therapy. The Oncologist 2021;25:1-11 Implications for Practice: The majority of invasive lobular breast cancers (ILCs) are hormone receptor (HR)-positive and low grade. Clinically, ILC is treated similar to HR-positive invasive ductal cancer (IDC). However, ILC differs distinctly from IDC in its clinicopathologic characteristics and molecular alterations. ILC also differs in response to systemic therapy, with studies showing ILC as less sensitive to chemotherapy. Patients with ILC have worse clinical outcomes with late recurrences. Despite these differences, clinical trials treat HR-positive breast cancers as a single disease, and there is an unmet need for studies addressing the unique challenges faced by patients diagnosed with ILC.

CRISPR/Cas9 genome editing can facilitate efficient deletion of genomic region, but it has not been used to delete an entire chromosome. Here, Adikusuma et al. show proof-of-concept for efficient CRISPR-mediated selective chromosome deletion by removing the centromere or shredding the chromosome arm in mouse embryonic stem cells and zygotes.

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Prognostic Level I. See Instructions for Authors for a complete description of levels of evidence.