Search

BACKGROUND: The definition of objective, clinically applicable evaluation criteria for FISH 1c/7c in laryngeal precursor lesions for the detection of chromosome instability (CI). Copy Number Variations (CNV) for chromosomes 1 and 7 reflect the general ploidy status of premalignant head and neck lesions and can therefore be used as a marker for CI.METHODS: We performed dual-target FISH for chromosomes 1 and 7 centromeres on 4 µm formalin-fixed, paraffin-embedded tissue sections of 87 laryngeal premalignancies to detect CNVs. Thirty-five normal head and neck squamous cell samples were used as a control. First, the chromosome 7:1 ratio (CR) was evaluated per lesion. The normal range of CRs (≥0.84 ≤ 1.16) was based on the mean CR +/- 3 x SD found in the normal population. Second, the percentage of aberrant nuclei, harboring > 2 chromosomes of chromosome 1 and/or 7 (PAN), was established (cut-off value for abnormal PAN ≥ 10%).RESULTS: PAN showed a stronger correlation with malignant progression than CR (resp. OR 5.6, p = 0.001 and OR 3.8, p = 0.009). PAN combined with histopathology resulted in a prognostic model with an area under the ROC curve (AUC) of 0.75 (s.e. 0.061, sensitivity 71%, specificity 70%).CONCLUSIONS: evaluation criteria for FISH 1c/7c based on PAN ≥ 10% provide the best prognostic information on the risk of malignant progression of premalignant laryngeal lesions as compared with criteria based on the CR. FISH 1c/7c detection can be applied in combination with histopathological assessment.

PD-L1, as assessed by immunohistochemistry, is a predictive biomarker for immuno-oncology treatment in lung cancer. Different scoring methods have been used to assess its status, resulting in a wide range of positivity rates. We use the European Thoracic Oncology Platform Lungscape non-small cell lung carcinoma cohort to explore this issue. PD-L1 expression was assessed via immunohistochemistry on tissue microarrays (up to four cores per case), using the DAKO 28-8 immunohistochemistry assay, following a two-round external quality assessment procedure. All samples were analyzed under the same protocol. Cross-validation of scoring between tissue microarray and whole sections was performed in 10% randomly selected samples. Cutoff points considered: ≥1, 50 (primarily), and 25%. At the two external quality assessment rounds, tissue microarray scoring agreement rates between pathologists were: 73% and 81%. There were 2008 cases with valid immunohistochemistry tissue microarray results (50% all cores evaluable). Concordant cases at 1, 25, and 50% were: 85, 91, and 93%. Tissue microarray core results were identical for 70% of cases. Sensitivity of the tissue microarray method for 1, 25, and 50% was: 80, 78, and 79% (specificity: 90, 95, 98%). Complete agreement between tissue microarrays and whole sections was achieved for 60% of the cases. Highest sensitivity rates for 1% and 50% cutoffs were detected for higher number of cores. Underestimation of PD-L1 expression on small samples is more common than overestimation. We demonstrated that classification of PD-L1 on small biopsy samples does not represent the overall expression of PD-L1 in all non-small cell cancer carcinoma cases, although the majority of cases are ‘correctly’ classified. In future studies, sampling more and larger biopsies, recording the biopsy size and tumor load may permit further refinement, increasing predictive accuracy.

Purpose It is known that despite efforts of improving adequate ablation in head and neck cancer, the local recurrence rate has not decreased sufficiently over the last two decades. This is partly due to the presence of potentially malignant groups of cells in the resection margins (minimal residual disease). Chromosomal instability (CI) detection in these histologically diagnosed tumour-free margins might help predict patients at risk for recurrence. Material and methods We have included 25 patients with oral squamous cell carcinoma (OSCC) treated with surgery alone between 1994 and 2003. All resections were histopathologically radical. Follow-up was documented for at least 5 years. Fluorescence in situ hybridization (FISH) was used to examine all resection margins of all tumours for the presence of CI, which is indicated by the nuclear detection of chromosome imbalances and/or polyploidization for chromosomes 1 and 7. In addition, tissue sections were analysed for p53 expression by immunohistochemistry. Results Of the 25 patients, 11 developed a recurrence. FISH analysis showed that of the 11 recurrences, 8 exhibited CI in at least one resection margin. This relation was significant with a p -value of 0.011. There was a trend for p53 overexpression in the resection margins of tumours with recurrence, however, this trend was not statistically significant ( p = 0.082). Conclusion CI in the resection margins of OSCCs, even though histologically tumour-free, can reliably identify patients at risk for developing a local or locoregional recurrence. A future goal will be to investigate how radiotherapy following surgery influences the prognosis of these patients.