ON THE COVER Surgeons in an operating room. For evaluation of tissues for potential cancer involvement, histopathologic analysis of tissue sections is commonly employed on surgical specimens, often intraoperatively through frozen section analysis. Mass spectrometry (MS) technologies have shown potential for cancer diagnosis. To be most useful, bringing MS closer to the patient or operating room would be a goal. Several ambient ionization techniques have been tested for intraoperative cancer diagnosis and surgical margin evaluation either through ex vivo tissue sections and tissue smears analyses. The use of smaller, lower-cost, and lower-performance mass spectrometers, such as a linear ion trap, could ease technology translation into the clinical space. This issue of Clinical Chemistry contains a clinical evaluation of a new handheld pen-like device, the MasSpec Pen, for ovarian cancer diagnosis across different sample sets, tissue types, and two different MS systems (orbitrap and linear ion trap). (See page 674.) Reproduced with permission. Copyright Dandelionus / Bigstock ID.