Abstract.The invasive front of carcinomas may vary in complexity from smooth to highly complex when the front splits up into small cell clusters or even single cancer cells. The degree of complexity is usually estimated visually and semiquantitatively by a pathologist, although more objective methods based on computer-assisted image analysis are available. In this study, we compared the visual estimation of the irregularity of the tumour invasion front of colon carcinomas to different quantitative image analytical techniques and defined a complexity index for the invasive margin. Sections from 29 archived colon carcinomas were stained immunohistochemically for cytokeratin 8. Images of the tumour invasion front were read into a computer and thresholded so that the tumour tissue became black and the background white or so that the tumour front was outlined by a single pixel line. The invasive front was visually classified into four degrees of irregularity by a pathologist. The complexity of the front was then assessed using four different image analysis techniques, i.e. the estimation of fractal dimension, tumour front length, number of tumour cell clusters and lacunarity. Fractal dimension and tumour cell clusters together gave the best correlation to visual grading using a discriminant analysis. A cluster analysis and a tree diagram analysis were then performed and were found to be superior to visual estimation. The clusters represent different degrees of complexity and the result of the tree diagram analysis can be used to assign complexity indices to colon tumours. The fractal dimension separated tumours up to a certain level (1.5-1.6) of complexity. When the tumour front split up into small cell clusters, the counting of tumour cell clusters separated the cells over and above the fractal dimension. This new technique can be used to objectively and quantitatively describe the complexity of the invasive front of tumours.

Adhesion proteins are responsible for the structural integrity of epithelial tissue and in tumors this integrity is often lost, resulting in a disorganization of the tissue. In the present study the complexity of the invasive front of colon carcinomas was correlated with cell adhesion protein expression and with polymorphisms in their genes. A complexity index was constructed from 32 colon carcinomas using computer-assisted morphometry estimating fractal dimension and tumor cell clusters followed by tree analysis. Immunohistochemical staining of beta-catenin, E-cadherin, occludin and claudin 2 was used for assessment of protein expression. Genetic screening of tissue from the tumor invasion front with laser microdissection was performed using SSCP and DNA sequencing. Adhesion protein distribution was significantly disturbed in most carcinomas. A single mutation in the gene of beta-catenin was found but there was no correlation between protein expression and genetic polymorphism. Nor was there any correlation between the complexity of the invasive border and protein distribution or genetic alterations. The results indicate that the complexity of colon carcinoma invasion is not dependent on genetic derangements in the genes of adhesion proteins or the protein distribution. Rather, aberrations in the function of other proteins related to the adhesive proteins could be responsible.

Tumor volume increases during growth and due to tumor progression various mutations appear that may cause phenotypic changes. The invasive pattern may thus be affected resulting in a more disorganized growth. This phenomenon might be due to mutations in the genome of the adhesion proteins, which are responsible for the structural integrity of epithelial tissue. Tumor volume was assessed in whole mount sections of 33 colon carcinomas using Cavalieri's principle. Images from the entire invasive border were captured and used for calculating the irregularity of the border (Complexity Index). The expression of the adhesion proteins E‐cadherin, β‐catenin, Claudin 2 and Occludin was assessed after immunohistochemical staining of two randomly selected areas of the invasive front of the tumor. Statistical significance for differences in volume was obtained for tumor Complexity Index, tumor stage (pT) and lymph node status (pN). Expression of adhesion proteins was significantly perturbed in the tumors compared with normal mucosa but only infrequently correlated to tumor differentiation or invasive pattern. The results show that when tumor volume increases the invasive pattern becomes more irregular which is compatible with tumor progression. A direct contribution of adhesion protein derangement to this process appears to be insignificant.

The diagnosis of gastrointestinal stromal tumors (GIST) is generally established on histopathologic examination of surgical specimens. The present study was undertaken to characterize the cytologic appearance of these tumors and to assess the utility of fine-needle aspirates, including immunocytochemistry for the demonstration of c-kit (CD117) and CD34, in the preoperative diagnosis. The study comprised preoperative fine-needle aspirates in three cases and aspirates performed on fresh surgical specimens in eight cases. The routinely stained smears revealed a mesenchymal cell population, predominated by spindle cells. In five of six cases a strong positivity for c-kit was demonstrated and in three of five cases a strong CD34expression was found in the tumor cells. These results show that fine-needle aspiration appears to be a useful method for the recognition and diagnosis of GISTs or ICC (interstitial cell of Cajal) tumors.

Sweden has experienced an unexpected &#x3e;30% increase in cervical cancer incidence among women with normal cytological screening results. We therefore performed a nationwide assessment of false-negative cytology before invasive cervical cancer. The Swedish national cervical screening registry identified 2,150 normal cytologies taken up to 10 years before 903 cases of invasive cervical cancer. The 27 cytological laboratories in Sweden were asked to rereview the slides, and all of them completed the rereview. One thousand nine hundred fifteen slides were retrieved and reviewed. Abnormalities were found in 30% of the slides, and the proportion of slides that had a changed diagnosis on rereview increased on average by 3.9% per sampling year during 2001–2016 (<i>p</i> &#x3c; 0.03). We also asked for rereview of normal smears taken up to 42 months before a histopathologically diagnosed high-grade squamous intraepithelial lesion (HSIL) or adenocarcinoma in situ (AIS). 19/27 laboratories responded, and out of 6,101 normal smears taken before HSIL/AIS, 5,918 were retrieved and rereviewed. The diagnosis was changed in 25% of cases. In summary, we found an increasing time trend of false-negative smears taken before invasive cervical cancer. This indicates a decreased protection of normal cytology in the screening program supporting earlier findings that this is the main reason behind the recent Swedish increase in cervical cancer. We suggest that optimal cervical cancer control may be promoted by routine nationally coordinated rereview of negative smears before high-grade cervical lesions or invasive cervical cancer.