Digital pathology is on the verge of becoming a mainstream option for routine diagnostics. Faster whole slide image scanning has paved the way for this development, but implementation on a large scale is challenging on technical, logistical, and financial levels. Comparative studies have published reassuring data on safety and feasibility, but implementation experiences highlight the need for training and the knowledge of pitfalls. Up to half of the pathologists are reluctant to sign out reports on only digital slides and are concerned about reporting without the tool that has represented their profession since its beginning. Guidelines by international pathology organizations aim to safeguard histology in the digital realm, from image acquisition over the setup of work-stations to long-term image archiving, but must be considered a starting point only. Cost-efficiency analyses and occupational health issues need to be addressed comprehensively. Image analysis is blended into the traditional work-flow, and the approval of artificial intelligence for routine diagnostics starts to challenge human evaluation as the gold standard. Here we discuss experiences from past digital pathology implementations, future possibilities through the addition of artificial intelligence, technical and occupational health challenges, and possible changes to the pathologist’s profession.

Usual ductal hyperplasia (UDH) of the breast is generally regarded as a nonneoplastic proliferation, albeit loss of heterozygosity has long been reported in a part of these lesions. To gain deeper insights into the molecular drivers of these lesions, an extended mutation profiling was performed. The coding regions of 409 cancer-related genes were investigated by next-generation sequencing in 16 cases of UDH, nine unassociated with neoplasia (classic) and seven arising within papillomas. Phosphatidylinositol 3-kinase/AKT/mammalian target of rapamycin (mTOR) activation was investigated by phosphorylated AKT, mTOR, and S6 immunohistochemistry. Of 16 lesions, 10 (63%) were mutated; 56% of classic lesions were unassociated with neoplasia, and 71% of lesions arose in papillomas. Fourteen missense mutations were detected: PIK3CA [6 (43%) of 14], AKT1 [2 (14%) of 14], as well as GNAS, MTOR, PIK3R1, LPHN3, LRP1B, and IGF2R [each 1 (7%) of 14]. Phosphorylated mTOR was seen in 83% and phosphorylated S6 in 86% of evaluable lesions (phospho-AKT staining was technically uninterpretable). In conclusion, UDH displays mutations of the phosphatidylinositol 3-kinase/AKT/mTOR axis at different levels, with PIK3R1, MTOR, and GNAS mutations not previously described. Specifically, oncogenic G-protein activation represents a yet unrecognized route to proliferation in UDH. On the basis of evidence of activating mutations, loss of heterozygosity, and a mass forming proliferation, we propose that UDH is most appropriately viewed as an early neoplastic intraductal proliferation.

Germline genetic testing for familial cancer syndromes is usually performed serially for the most likely genetic causes. In recent years the way genetic testing carried out has changed, as next generation sequencing now allows the simultaneous testing of multiple susceptibility genes at low costs.

Overexpression the KCNJ3, a gene that encodes subunit 1 of G-protein activated inwardly rectifying K+ channel (GIRK1) in the primary tumor has been found to be associated with reduced survival times and increased lymph node metastasis in breast cancer patients. In order to survey possible tumorigenic properties of GIRK1 overexpression, a range of malignant mammary epithelial cells, based on the MCF-7 cell line that permanently overexpress different splice variants of the KCNJ3 gene (GIRK1a, GIRK1c, GIRK1d and as a control, eYFP) were produced. Subsequently, selected cardinal neoplasia associated cellular parameters were assessed and compared. Adhesion to fibronectin coated surface as well as cell proliferation remained unaffected. Other vital parameters intimately linked to malignancy, i.e. wound healing, chemoinvasion, cellular velocities / motilities and angiogenesis were massively affected by GIRK1 overexpression. Overexpression of different GIRK1 splice variants exerted differential actions. While GIRK1a and GIRK1c overexpression reinforced the affected parameters towards malignancy, overexpression of GIRK1d resulted in the opposite. Single channel recording using the patch clamp technique revealed functional GIRK channels in the plasma membrane of MCF-7 cells albeit at very low frequency. We conclude that GIRK1d acts as a dominant negative constituent of functional GIRK complexes present in the plasma membrane of MCF-7 cells, while overexpression of GIRK1a and GIRK1c augmented their activity. The core component responsible for the cancerogenic action of GIRK1 is apparently presented by a segment comprising aminoacids 235–402, that is present exclusively in GIRK1a and GIRK1c, but not GIRK1d (positions according to GIRK1a primary structure). The current study provides insight into the cellular and molecular consequences of KCNJ3 overexpression in breast cancer cells and the mechanism upon clinical outcome in patients suffering from breast cancer.

Inter-test concordance between the MammaPrint and the EndoPredict tests used to predict the risk of recurrence in breast cancer was evaluated in 94 oestrogen receptor-positive, HER2-negative breast cancers. We correlated histopathological data with clinical risk estimation as defined in the MINDACT trial. 42.6% (40/94) of cases were high-risk by MammaPrint, 44.7% (42/94) by EndoPredict (EPclin), and 45.7% (43/94) by clinical risk definition. Thirty-six percent of genomic risk predictions were discordant with a low inter-test correlation between EndoPredict and MammaPrint (p = 0.012; κ = 0.27, 95% CI [0.069, 0.46]). Clinical risk stratification did not correlate with MammaPrint (p = 0.476) but highly correlated with EndoPredict (p < 0.001). Consequently, clinically high-risk tumours (n = 43) were more frequently high-risk by EndoPredict than by MammaPrint (76.6% vs. 46.5%, p = 0.004), with 44% of cases discordantly classified and no significant association between genomic risk predictions (p = 0.294). Clinicians need to be aware that clinical pre-stratification can profoundly influence multigenomic test performance.