Table 3.

Recommendations of the TILs Working Group’s for assessing TILs in breast (for further detail see Salgado et al. [96])

1. One section (4–5 μm, magnification 200×–400×) per patient is considered to be sufficient. Full sections are preferred over biopsies (in pretherapeutic neoadjuvant setting, cores can be used); currently, no validated methodology has been developed to score TILs after neoadjuvant treatment

2. TILs should be reported for the stromal compartment (% stromal TILs). The denominator used to determine the % stromal TILs is the area of stromal tissue

3. TILs should be evaluated exclusively within the borders of the invasive tumour, excluding TILs around ductal carcinoma in situ or normal lobules and zones with artefacts, necrosis, hyalinisation as well as the previous biopsy site

4. All mononuclear cells (including lymphocytes and plasma cells) should be scored, but polymorphonuclear leukocytes are excluded

5. A full assessment of average TILs in the tumour area should be used

6. It should be scored as a continuous variable that will allow categorise different thresholds and more accurate statistical analyses

TILs tumour-infiltrating lymphocytes