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Immunohistochemical and molecular analyses of HER2 status in breast cancers are highly concordant and complementary approaches.

Lehmann-Che J, Amira-Bouhidel F, Turpin E, Antoine M, Soliman H, Legres L, Bocquet C, Bernoud R, Flandre E, Varna M, de Roquancourt A, Plassa LF, Giacchetti S, Espié M, de Bazelaire C, Cahen-Doidy L, Bourstyn E, Janin A, de Thé H, Bertheau P - Br. J. Cancer (2011)

Bottom Line: Twelve out of 466 cases (3%) revealed discordances between the two methods.The power of Q-RT-PCR to predict HER2 status (defined by seven methods) was similar to that of IHC.Q-RT-PCR and IHC are highly concordant methods for HER2 status assessment, and Q-RT-PCR allows a highly reliable quantitative assessment and could be a useful adjunct to IHC.

View Article: PubMed Central - PubMed

Affiliation: AP-HP, Hosp Saint-Louis, Department of Biochemistry, Paris 75010, France. jacqueline.lehmann-che@sls.aphp.fr

ABSTRACT

Background: Immunohistochemistry (IHC) and fluorescent in situ hybridisation (FISH) are currently the most commonly used methods to assess HER2 status. PCR-based assays allow quantitative determination of HER2 amplification (Q-PCR) or overexpression (Q-RT-PCR), but are not routinely used. We evaluated the relevance of Q-RT-PCR for HER2 status determination.

Methods: We compared IHC and Q-RT-PCR in 466 breast tumours. In discordant or equivocal cases, five additional methods (IHC with two other antibodies, FISH, silver in situ hybridisation (SISH) and Q-PCR) were combined to determine HER2 status. Two cases with HER2 intra-tumour heterogeneity were further explored by allelic profiles analysis and HUMARA clonality determination after microdissection.

Results: We observed 97.3% concordance between Q-RT-PCR and non-equivocal IHC. Twelve out of 466 cases (3%) revealed discordances between the two methods. The power of Q-RT-PCR to predict HER2 status (defined by seven methods) was similar to that of IHC. Although rare, some discordances between techniques might be due to HER2 intra-tumour heterogeneity and we report two examples, one tumour containing two distinct clones, another tumour consisting of HER2 amplified and non-amplified subclones.

Conclusion: Q-RT-PCR and IHC are highly concordant methods for HER2 status assessment, and Q-RT-PCR allows a highly reliable quantitative assessment and could be a useful adjunct to IHC.

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Related in: MedlinePlus

Comparison of HER2 determination by IHC (CB11) and Q-RT–PCR on 466 breast tumours treated in St Louis Hospital. (A) Distribution of tumour samples according to HER2 status assessed on formalin-fixed, paraffin-embedded samples with 0/1+, 2+ and 3+ IHC scores and Q-RT–PCR on fresh frozen samples, with a cut-off ratio of 7. (B) HER2 Q-RT–PCR ratio according to the three IHC score groups: each box shows the 25–75th percentile (box extremities), the median values (line in the box and value outside) and the lowest and highest values (bottom and top bars of the whisker).
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fig1: Comparison of HER2 determination by IHC (CB11) and Q-RT–PCR on 466 breast tumours treated in St Louis Hospital. (A) Distribution of tumour samples according to HER2 status assessed on formalin-fixed, paraffin-embedded samples with 0/1+, 2+ and 3+ IHC scores and Q-RT–PCR on fresh frozen samples, with a cut-off ratio of 7. (B) HER2 Q-RT–PCR ratio according to the three IHC score groups: each box shows the 25–75th percentile (box extremities), the median values (line in the box and value outside) and the lowest and highest values (bottom and top bars of the whisker).

Mentions: To determine HER2 status, we performed immunohistochemistry with CB11 antibody and Q-RT–PCR on all 466 cases (Figure 1). Overall concordance was excellent (97.3%), especially in IHC 0,1+ subgroup (348 negative Q-RT–PCR/351 IHC 0/1+: 99.2%). Concordance was also good in IHC 3+ cases (91%: 92 positive Q-RT–PCR/101 IHC 3+). However, in 12 out of 466 cases (3%), the two techniques were discordant (either IHC 0,1+/Q-RT–PCR>7 or IHC 3+/Q-RT–PCR<7). Among these 12 discordant cases, 11 had been obtained after surgical procedure and only one after fine-needle biopsy. In the 14 out of 466 IHC 2+ equivocal cases, Q-RT–PCR showed the absence of HER2 overexpression in 13 out of 14 cases (93%).


Immunohistochemical and molecular analyses of HER2 status in breast cancers are highly concordant and complementary approaches.

Lehmann-Che J, Amira-Bouhidel F, Turpin E, Antoine M, Soliman H, Legres L, Bocquet C, Bernoud R, Flandre E, Varna M, de Roquancourt A, Plassa LF, Giacchetti S, Espié M, de Bazelaire C, Cahen-Doidy L, Bourstyn E, Janin A, de Thé H, Bertheau P - Br. J. Cancer (2011)

Comparison of HER2 determination by IHC (CB11) and Q-RT–PCR on 466 breast tumours treated in St Louis Hospital. (A) Distribution of tumour samples according to HER2 status assessed on formalin-fixed, paraffin-embedded samples with 0/1+, 2+ and 3+ IHC scores and Q-RT–PCR on fresh frozen samples, with a cut-off ratio of 7. (B) HER2 Q-RT–PCR ratio according to the three IHC score groups: each box shows the 25–75th percentile (box extremities), the median values (line in the box and value outside) and the lowest and highest values (bottom and top bars of the whisker).
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Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3111154&req=5

fig1: Comparison of HER2 determination by IHC (CB11) and Q-RT–PCR on 466 breast tumours treated in St Louis Hospital. (A) Distribution of tumour samples according to HER2 status assessed on formalin-fixed, paraffin-embedded samples with 0/1+, 2+ and 3+ IHC scores and Q-RT–PCR on fresh frozen samples, with a cut-off ratio of 7. (B) HER2 Q-RT–PCR ratio according to the three IHC score groups: each box shows the 25–75th percentile (box extremities), the median values (line in the box and value outside) and the lowest and highest values (bottom and top bars of the whisker).
Mentions: To determine HER2 status, we performed immunohistochemistry with CB11 antibody and Q-RT–PCR on all 466 cases (Figure 1). Overall concordance was excellent (97.3%), especially in IHC 0,1+ subgroup (348 negative Q-RT–PCR/351 IHC 0/1+: 99.2%). Concordance was also good in IHC 3+ cases (91%: 92 positive Q-RT–PCR/101 IHC 3+). However, in 12 out of 466 cases (3%), the two techniques were discordant (either IHC 0,1+/Q-RT–PCR>7 or IHC 3+/Q-RT–PCR<7). Among these 12 discordant cases, 11 had been obtained after surgical procedure and only one after fine-needle biopsy. In the 14 out of 466 IHC 2+ equivocal cases, Q-RT–PCR showed the absence of HER2 overexpression in 13 out of 14 cases (93%).

Bottom Line: Twelve out of 466 cases (3%) revealed discordances between the two methods.The power of Q-RT-PCR to predict HER2 status (defined by seven methods) was similar to that of IHC.Q-RT-PCR and IHC are highly concordant methods for HER2 status assessment, and Q-RT-PCR allows a highly reliable quantitative assessment and could be a useful adjunct to IHC.

View Article: PubMed Central - PubMed

Affiliation: AP-HP, Hosp Saint-Louis, Department of Biochemistry, Paris 75010, France. jacqueline.lehmann-che@sls.aphp.fr

ABSTRACT

Background: Immunohistochemistry (IHC) and fluorescent in situ hybridisation (FISH) are currently the most commonly used methods to assess HER2 status. PCR-based assays allow quantitative determination of HER2 amplification (Q-PCR) or overexpression (Q-RT-PCR), but are not routinely used. We evaluated the relevance of Q-RT-PCR for HER2 status determination.

Methods: We compared IHC and Q-RT-PCR in 466 breast tumours. In discordant or equivocal cases, five additional methods (IHC with two other antibodies, FISH, silver in situ hybridisation (SISH) and Q-PCR) were combined to determine HER2 status. Two cases with HER2 intra-tumour heterogeneity were further explored by allelic profiles analysis and HUMARA clonality determination after microdissection.

Results: We observed 97.3% concordance between Q-RT-PCR and non-equivocal IHC. Twelve out of 466 cases (3%) revealed discordances between the two methods. The power of Q-RT-PCR to predict HER2 status (defined by seven methods) was similar to that of IHC. Although rare, some discordances between techniques might be due to HER2 intra-tumour heterogeneity and we report two examples, one tumour containing two distinct clones, another tumour consisting of HER2 amplified and non-amplified subclones.

Conclusion: Q-RT-PCR and IHC are highly concordant methods for HER2 status assessment, and Q-RT-PCR allows a highly reliable quantitative assessment and could be a useful adjunct to IHC.

Show MeSH
Related in: MedlinePlus