These guidelines supplement existing guidelines on HER2 testing by immunohistochemistry and in-situ hybridisation(ISH) methods in the UK. They provide a specific focus on aspects of guidance relevant to HER2 ISH testing methods, both fluorescent and chromogenic. They are formulated to give advice on methodology, interpretation and quality control for ISH-based testing of HER2 status in common tumour types, including both breast and gastric tumours. The aim is to ensure that all ISH-based testing is accurate, reliable and timely.National and international guidelines and recommendations highlight the importance of quality control, accuracy and reproducibility in the determination of HER2 status in breast and gastric carcinomas. 1e5 The value of HER2 in-situ hybridisation (ISH) testing is that it provides a robust, accurate and highly clinically informative measure of HER2 status in clinical samples. While debate continues as to the optimal testing regime and the relative importance of HER2 detection by immunohistochemistry versus ISH 1e4 all guidelines recognise that for breast cancers with equivocal immunohistochemistry results HER2 testing by ISH is mandatory.1e5 While current National Institute for Health and Clinical Excellence guidelines recommend immunohistochemical detection of HER2 in gastric carcinoma, and therapy with trastuzumab only for patients with metastatic disease who have tumours with high (3+) immunodetectable HER2 expression, the current UK licence for herceptin in gastric cancer permits treatment of both immunohistochemistry positive (3+) and fluorescence in-situ hybridisation (FISH; immunohistochemistry 2+ amplified) positive cases as follows: 'Herceptin should only be used in patients with metastatic gastric cancer whose tumours have HER2 overexpression as defined by IHC2+ and a confirmatory SISH or FISH result, or by an IHC3+ result. Accurate and validated assay methods should be used. ' There is now a growing number of commercial kits using both chromogenic and fluorescent detection systems for the ISH analysis of HER2.

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Background:The epidermal growth factor receptor (EGFR) is expressed in ovarian cancer, but agents targeting this pathway have shown little effect as single agents. This may be due to the presence of alternative pathways, particularly activation of the PI3K/Akt/MTOR pathway.Methods:We have therefore examined the effect of inhibitors of this pathway (ZSTK474 and sirolimus) in combination with the EGFR inhibitors erlotinib and gefitinib in ovarian cancer primary cell cultures.Results:The single-agent EGFR inhibitors showed little activity, although some activity was seen with the single-agent PI3K inhibitor, ZSTK474. Combinations of ZSTK474 with EGFR inhibitors showed enhanced activity with some evidence of synergy, whereas sirolimus combinations were less active. The results were not explicable on the basis of PIK3CA mutation or amplification, or PTEN loss, although one tumour with a KRAS mutation showed resistance to EGFR inhibitors. However, there was correlation of the EGFR expression with sensitivity to EGFR and resistance to PI3K active agents, and inverse correlation in the sensitivity of individual tumours to agents active against these pathways, suggesting a mechanism of action for the combination.Conclusion:Phase I/II clinical trials with these agents should include further pharmacodynamic endpoints and molecular characterisation to identify patients most likely to benefit from this strategy.

FISH is very useful in classifying equivocal conjunctival melanocytic lesions, especially those with atypical junctional activity and naevoid melanocytic proliferations of the conjunctiva.

Oligodendrogliomas may be divided into those with deletion of chromosomes 1p and 19q (Del+), and those without (Del¡). Del+ tumours show better survival and chemoresponsiveness but the reason for this diVerence is unknown. We have investigated whether these subgroups diVer in (a) apoptotic index, (b) the proportion of cells licensed for DNA replication but not in-cycle, and (c) the relative length of G 1 -phase. Fluorescence in situ hybridisation with probes to 1p and 19q was used to determine the deletion status of 54 oligodendrogliomas, including WHO grades II and III. The apoptotic index was determined using counts of apoptotic bodies. Replication-licensed non-proliferating cells were determined from the Mcm2 minus Ki67 labelling index, whilst the geminin to Ki67 ratio was used as a measure of the relative length of G 1 . Del+ oligodendrogliomas showed a higher apoptotic index than Del¡ tumours (P = 0.037); this was not accounted for by diVerences in tumour grade or in proliferation. There were no diVerences in the Mcm2 ¡ Ki67 index or in the geminin/Ki67 ratio between the subgroups, but grade III tumours showed a higher proportion of licensed non-proliferating cells than grade II tumours (P = 0.001). An increased susceptibility to apoptosis in oligodendrogliomas with 1p § 19q deletion may be important in their improved clinical outcome compared to Del¡ tumours.