The Hedgehog (Hh) pathway is a main regulation cascade in embryonic differentiation. It is also present in adult tissues and unusual expression has been associated with formation of benign and malignant lesions. We examined the presence of the Hedgehog pathway in normal and pathological human colon tissue. Components investigated include Sonic (Shh), Indian (Ihh), and Desert Hedgehog (Dhh), Gli1, Gli2, Gli3, and Patched (Ptch). Pathological tissue samples comprised 23 benign and 20 malignant lesions of human colon. The influence of the Hedgehog pathway on differentiation and proliferation has been investigated by analyzing the effect of the pathway inhibitor Cyclopamine on human colon cancer cell lines HT29 and CaCo2. In normal colon, we detected expression of Shh and Dhh within the lining epithelium and Patched, Gli1, and Gli2 along the whole crypts. Within all benign lesions, positive staining of Shh, Dhh, Gli1, Gli2, and Ptch was detected. Expression of Shh and Dhh was restricted to single cell aggregates. Malignant lesions also displayed focal staining pattern for Shh and Dhh but to a much lesser extent. We conclude that Hedgehog signaling is involved rather in constant differentiation and renewing of the colonic lining epithelium than in cancer formation, growth, or proliferation.

D5F3 with OptiView exclusively stained rearranged cases with strong intensity, without a single false-positive or false-negative case. The number of subsequent ALK FISH analyses required would have decreased from 303 to 14 cases (-95.4%), reducing significantly the time, work and costs without any loss of diagnostic quality and accuracy.

Between 2002 and 2005, we made 343 intraoperative frozen section diagnoses with a telepathology system, which connected a neurosurgical department to our department of pathology. An expert neuropathologist performed at least one brief gross examination, and this was followed by a smear preparation and a frozen section slide for each case. Frozen section diagnosis lasted on average 26.1 min, calculated from the beginning of gross examination until the surgeon was given the diagnosis. The majority of cases (283 or 83%) were diagnosed in 15-40 min. The mean time needed for macroscopic examination was 3.0 min, time for staining 4.2 min, smear diagnosis took 5.4 min and time for histological diagnosis 10.7 min. Telemicroscopy of a smear slide took 11 times longer compared with light microscopy, and telemicroscopy of a frozen section slide took 16 times longer than with light microscopy. In 6% of cases, the telepathology software posed technical problems, which delayed the time of diagnosis, but not by more than 4 min. We were able to render a diagnosis in all cases (system reliability 100%). After eliminating sampling errors (i.e. cases with no diagnostic material in the frozen section slides and/or in smear preparations), the diagnostic accuracy for telepathology was 97.9%.

We evaluated a dynamic telepathology system in routine use after a two-year developmental phase. In two three-month studies, two years apart, all intraoperative frozen sections were examined by one pathologist via the telepathology system. Laboratory technicians sampled tissues at gross examination and were connected with the pathologist by videoconference. Specimens were immediately reviewed after the telepathology diagnosis by the same diagnostician. In the second study there were 342 cases. The mean time required to diagnose small specimens such as biopsies was 8 min (range 4-14); for specimens with extensive gross examination it was 22 min (range 10-45). The telepathology and traditional frozen-section diagnoses agreed in 99.4% of cases, but telepathology took two to four times longer for gross and histological examinations, and up to 10 times longer for histological examination only. There were five false diagnoses (1.5%), two of which originated from telepathology (0.6%) and were recognized in the subsequent light microscopy review. Telepathology is not a replacement for light microscopy, but should be regarded as a complementary technique.