1. Case 6
A 49 year old female was found to have a 1.3 cm spiculated mass on screening mammogram
Ultrasound revealed a 1.2 cm hypoechoic mass with posterior shadowing and irregular margins
Core needle biopsy revealed a 1.4 cm, grade 2, invasive ductal carcinoma that was ER+, PR- and HER2-
Subsequent excision confirmed the tumor size and grade; No LVI was identified
A sentinel lymph node was negative
The medical oncologist requests OncotypeDX

2. Case 6
A 49 year old female was found to have a 1.3 cm spiculated mass on screening mammogram
Ultrasound revealed a 1.2 cm hypoechoic mass with posterior shadowing and irregular margins
Core needle biopsy revealed a 1.4 cm, grade 2, invasive ductal carcinoma that was ER+, PR- and HER2-
Subsequent excision confirmed the tumor size and grade; No LVI was identified
A sentinel lymph node was negative
The medical oncologist requests OncotypeDX

3. “Luminal B-like Tumor”
Case 6
ER strongly positive; 90% of tumor cell nuclei stained
PR negative
HER2 negative
“Luminal B-like Tumor”
Caveat:
“Attempts to reproduce the intrinsic subtype distinction between Luminal A-like and Luminal B-like using conventional pathology have proved impractical”- St. Gallen, 2015

4. Luminal B Breast Carcinoma
~10% of breast cancers
ER positive
Tend to be higher grade and/or have a higher proliferation index
May overexpress HER2 (Luminal B, HER2+)
High expression of hormone receptors and associated genes
Respond to endocrine and chemotherapy
Prognosis not as good as for Luminal A
Sorlie, 2001

5. Immunophenotyping to Approximate Molecular Subtype Maisonneuve, BCR, 2014 Coates, Ann Oncol, 2015
Luminal A
ER+, HER2-,
Ki-67<14% or Ki-67 intermediate (14-19%) and PR>20%,
Luminal B
ER+, HER2-
Ki-67 intermediate (*14-19%) and PR- or low (<20%) or Ki-67>20%
HR+, HER2+
HER2 enriched
ER-, PR-, HER2+
Basal-like
ER-, PR-, HER2-, [CK5/6+ and/or EGFR+]
*St. Gallen, 2015 considers PR 20-29% to be intermediate

6. Luminal B Breast Carcinoma
<
Ades, JCO, 2014

7. Molecular Classification Implications for Prognosis

8. Molecular Classification
2016
Breast Cancer
Estrogen Receptor
Negative Cancers
Positive Cancers
Basal-like
ER, PR, HER2
negative
HER2 Enriched
HER2+
ER/PR absent
Luminal B-like
LB-HER2-: ER+/HER2-,
Either Ki-67 high or
Ki-67 intermediate and PR-/low
LB-HER2+: ER+/ HER2+
Any Ki-67, Any PR
Luminal A-like
ER+, HER2- and
Ki-67 low or
Ki-67 intermediate
and PR high

9. Molecular classification has prognostic significance
Ciriello, BCRT, 2013
Sorlie, 2003

10. Commercially Available Multigene Signatures
Van de Vijver, 2014

11. OncotypeDx (Genomic Health, Inc.) <18 Low 18-31 Intermediate
RS = x HER2 group score
-0.34 x ER group score
+1.04 x proliferation group score
+0.10 x invasion group score
+0.05 x CD68
x GSMT1
x BAG1
<18 Low
18-31 Intermediate
>31 High
NEJM 2004;351:2817

12. Recurrence Score and Prognosis
in ER+, N- Breast Cancer
Paik, 2004

13. Drukker, BCRT, 2014
Expression signature consisting of 70 genes identified good and poor prognosis groups among both N- and N+ patients
Better than standard prognostic systems based on clinical and histologic features (e.g., St. Gallen, NIH)
MammaPrint
(Agendia)
NEJM, 2002

14. Prognostic value independent of: Nodal status Size Grade ER status
J Clin Oncol 2009
Prognostic value independent of:
Nodal status
Size
Grade
ER status
Predicted benefit from neoadjuvant chemotherapy
PAM50 Assay

15. Which Expression Signature is Best? Fan, NEJM, 2006
Five different gene-expression based models compared among a single set of 295 samples
High level of concordance in outcome prediction
But, very little overlap in genes

16. Which Expression Signature is Best? Fan, NEJM, 2006
OncotypeDX
Mammaprint
Wound Healing

17. Proliferation genes are the common driving force in all prognostic signatures
Factors associated with tumor burden (size, nodal status) remain independently associated with prognosis
Breast Cancer Res 2008

18. Comparison of 47 published breast cancer signatures with 1,000 randomly generated signatures
>90% of signatures predicted breast cancer outcome; 60% of random ones performed better than original signatures
Prognostic signatures do not identify specific mechanisms, rather all signatures, even random ones, are proliferation related and able to discriminate prognosis
PLoS, 2011

19. Most can be performed on FFPE
Relevance to Clinical Practice Are Expression Signatures Ready for Routine Clinical Use?
Most can be performed on FFPE
Almost all available data from retrospective analyses
Prognostic value time dependent (reduced between 5-10 years)
Cost

20. Relevance to Clinical Practice
Which patients?
All signatures more useful for assessing prognosis in ER+ cancers (i.e., luminal) and are of little value in ER- cancers (i.e., HER2 and basal molecular types)

21. Relevance to Clinical Practice
Is this approach really better than using a combination of clinical and pathologic factors supplemented by appropriate biomarkers detected by IHC (e.g., ER, PR, HER2 and Ki67)?

22. IHC4 Score Cuzick, JCO, 2011
1125 pts with ER+ breast cancer in the TransATAC trial
ER, PR, HER2 and Ki67 assessed by IHC
Combined “IHC4 Score” provided similar prognostic information as OncotypeDX Recurrence Score

23. Surrogate Histologic and IHC Markers in Clinical Practice-Ki67
Proliferation markers used to differentiate Luminal A from Luminal B
Unlike ER and HER2 which show bimodal distribution with clear cutpoints, proliferation determined by several genes with continuous distribution

24. Surrogate Histologic and IHC Markers in Clinical Practice-Ki67
Tumor grade most widely used as a surrogate for proliferation
Ki67 most widely used proliferation marker
No consensus on cutpoint or method of counting
?Better to utilize prognostic signature in this scenario

25. More patients scored as high risk and fewer as intermediate risk
JCO, 2013
PAM50 Risk of Recurrence (ROR) Score provided more prognostic information in endocrine-treated, ER+, node- patients than OncotypeDx recurrence score, especially in HER2- group
More patients scored as high risk and fewer as intermediate risk

26. JCO, 2013

27. Validation of Nanostring’s Prosigna Assay PAM50 ROR
Nielsen, Clin Cancer Research, 2014
Wallden, BMC Med Genomics, 2015
The analytical performance of the Prosigna assay based on PAM50 has been validated using FFPE across multiple laboratories
Accurate prediction of risk of distant recurrence among women with ER+ breast cancer treated with 5 yrs of tamoxifen (prognostic beyond 5 years)
Able to classify tumors according to intrinsic subtype

28. Alvarado, Adv Ther, 2015

29. Alvarado, Adv Ther, 2015

30. Multigene Signatures and Predictive Factors

31. Recurrence Score and Chemotherapy Benefit
In ER+, N- Breast Cancer
Paik, 2006
Low
Int
High

32. Being used clinically with increasing frequency
2015
Being used clinically with increasing frequency
OncotypeDX RS used most often to identify patients with ER+ breast cancer who may safely be spared cytotoxic therapy (i.e., those with low recurrence score)

33. Current Clinical Status of Expression Signatures For Selecting Treatment
“For patients with ER+ early breast cancer the benefits of OncotypeDX outweigh the acquisition costs” (Rouzier, BCRT, 2013)
“It is one step more toward precision” (Hudis, NEJM, 2015)

34. Where are we today?
ER, PR and HER2 status are the major drivers of clinical decision making regarding the type of systemic therapy
OncotypeDx used in some patients with ER+ breast cancer to determine the need for chemotherapy

35. Where are we today?
Targeted sequencing for genomic alterations/mutations in patients with metastatic disease to determine eligibility for clinical trials (e.g. for PI3 kinase inhibitors)

36. Signaling Pathways Under Blockade in Luminal Cancers
Ades, JCO, 2014

37. Chemotherapy Benefit?
Three prospective randomized trials-MINDACT, TAILORx and RxPONDER- are testing the usefulness of gene signatures in predicting benefit from adjuvant chemotherapy in patients with ER+ breast cancer
Results anticipated

38. Conclusions Molecular pathology has:
Furthered our understanding of breast cancer molecular mechanisms
Provided insight into the development of targeted therapies
A role in determining prognosis and predicting response to therapy
Incorporation of expression signatures into clinical practice is here

39. Lesions that may mimic Invasive Carcinoma
Conclusions
Lesions that may mimic Invasive Carcinoma
For optimal patient care, we should be thinking about breast cancer according to the molecular subtypes (or the clinicopathologic correlate) with the associated prognostic and therapeutic implications