title: Tumor-infiltrating lymphocytes predict response to anthracycline-based chemotherapy in estrogen receptor-negative breast cancer.
abstract: BACKGROUND
  Infiltration of breast tumors by tumor-infiltrating lymphocytes (TIL) has been associated with sensitivity to anthracycline-based chemotherapy. However, it is unclear whether this is true within the estrogen receptor-alpha (ER)-negative subset of breast tumors that frequently manifest high TIL levels.
  
  
  METHODS
  The association of TIL with short-term and long-term clinical response to anthracycline-based therapy was assessed in two independent ER-negative breast cancer cohorts in which patients were categorized as TIL-high or TIL-low. We defined an eight-gene lymphocyte mRNA expression signature (including CD19, CD3D, CD48, GZMB, LCK, MS4A1, PRF1, and SELL) and used unsupervised hierarchical clustering to examine the association between TIL and short-term response to neoadjuvant chemotherapy in a previously published cohort of ER-negative tumors (n = 113). We also examined the association between TIL and long-term chemotherapeutic efficacy in a second cohort of ER-negative tumors (n = 255) with longer than 6 years of median follow-up by using tissue microarrays and immunohistochemistry (IHC) for detection of CD3, CD8, CD4, CD20, and TIA-1.
  
  
  RESULTS
  In patients with ER-negative tumors treated with neoadjuvant anthracycline-based chemotherapy, pathologic complete responses (pCRs) were achieved by 23 (74%) of 31 TIL-high patients and 25 (31%) of 80 TIL-low patients (odds ratio (OR), 6.33; 95% confidence interval (CI), 2.49 to 16.08; P < 0.0001). Multivariate logistic regression with standard clinicopathologic features demonstrated that only tumor size (P = 0.037) and TIL status (P = 0.001) were independent predictors of anthracycline response. In the second cohort, adjuvant anthracycline-based therapy was associated with increased disease-free survival (DFS) only in patients with high levels of intraepithelial CD3+ TIL (P = 0.0023). In contrast, outcomes after CMF treatment (cyclophosphamide, methotrexate, and fluorouracil) showed no association with CD3 status. In both cohorts, cytotoxic T-cells were the primary TIL subtype associated with anthracycline sensitivity. Finally, TIL significantly predicted anthracycline sensitivity for both the Her2-positive and triple-negative tumor phenotypes.
  
  
  CONCLUSIONS
  ER-negative breast cancers with high levels of TIL have heightened sensitivity to anthracycline-based chemotherapy, as assessed by the immediate response to neoadjuvant therapy and long-term outcome following adjuvant therapy. Investigations of TIL-based predictive tests to identify patients likely to benefit from anthracycline-based treatments are warranted.
authors.affiliation: Trev & Joyce Deeley Research Centre, British Columbia Cancer Agency, Victoria, British Columbia, V8R 6V5, Canada.
authors.forename: Nathan R
authors.initials: NR
authors.lastname: West
authors.forename: Katy
authors.initials: K
authors.lastname: Milne
authors.forename: Pauline T
authors.initials: PT
authors.lastname: Truong
authors.forename: Nicol
authors.initials: N
authors.lastname: Macpherson
authors.forename: Brad H
authors.initials: BH
authors.lastname: Nelson
authors.forename: Peter H
authors.initials: PH
authors.lastname: Watson
mesh_terms: D000328:Adult; D000368:Aged; D018943:Anthracyclines / Q000627:therapeutic use*; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D001943:Breast Neoplasms / Q000175:diagnosis* / Q000188:drug therapy* / Q000401:mortality; D016000:Cluster Analysis; D015331:Cohort Studies; D005260:Female; D020869:Gene Expression Profiling; D006801:Humans; D016246:Lymphocytes, Tumor-Infiltrating / Q000145:classification / Q000378:metabolism / Q000473:pathology*; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D009367:Neoplasm Staging; D011379:Prognosis; D011960:Receptors, Estrogen / Q000378:metabolism*; D016019:Survival Analysis; D013602:T-Lymphocytes, Cytotoxic / Q000378:metabolism / Q000473:pathology; D016896:Treatment Outcome
chemical_list: D018943:Anthracyclines; D000970:Antineoplastic Agents; D011960:Receptors, Estrogen