HER-2 detection FISH vs CISH

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HER-2 detection FISH vs CISH

• Mentor Dr David Thomson

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What is

• Tests to detect HER ( human epidermal growth
  factor receptor ) positivity in breast cancer
• FISH -fluroscence in situ hybridisation
• CISH - chromogenic in situ hybridisation

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.

• Since October 1st ,2006
• (trastuzumab) Herceptin is available on the PBS
  for early breast cancer
• Treatment cost A 60,000 a year
• 20 of breast cancers are HER2 ve
• 13,000 breast cancers diagnosed each year

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HER-2 testing process
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Specificity of IHC

• 2- 5 of HER 2 negative( IHC 0/ 1 ) may be FISH
  positive
• 5 of ( 3 IHC ) FISH negative
• 2 results unpredictable

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protocol
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How effective

• Herceptin reduced cancer recurrence by 50 when
  compared to chaemotherapy alone in HER2ve
  patients
• HER 2 positivity detected by FISH gave the best
  correlation of tumour response to Herceptin

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FISH -disadvantages

• Modern expensive fluroscence microscope with
  filters
• ( St Vincents only centre in NSW )
• Fluroscence fades quickly (photographic
  record required )
• Morpological features difficult to visualise

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CISH

• Bright field microscope used
• Permanent record
• Histological analysis similar to
  immunohistochemistry

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Study comparing FISH CISH

• Department of Pathology (UDIAT centre )
• Barcelona Spain
• Article Breast ( 2006 ) 15, 519-527

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study

• 200 cases of invasive breast cancer
  retrospectively selected
• IHC ( immunohistochemistry )
• 2 43
• 3 62
• 0/1 95

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.

• Microchops treated
• FISH and CISH technique as per the manufacture
  guidelines
• Slides were examined by 2 different breast
  pathologists

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results

• 174 tumours analysed
• 39 positive for FISH and CISH
• 126 negative for FISH and CISH
• 1 FISH negative CISH positive
• 8 CISH positive FISH negative
• Concordance 94.8

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.

• 7 cases of FISH ve ( CISH -ve)was due to Cr 17
  polysomy, one case of CISH showed low amplication
• Negative FISH ( CISH ) revaluation showed low
  amplication FISH

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results

• 26 cases were not assessable
• 16 had inadequate tumour sample
• 10 cases no hybridisation signals

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Drawback of study

• Retrospective analysis of cases in one institute
• Both Pathologists were from same institute

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Herceptin protocol for Early breast cancer

• HER 2 positivity established by ISH test
• Patient should also have received chaemotherapy