Clinicopathological features of breast cancer in Japanese female patients with Lynch syndrome.

Kanaya N1,2, Tanakaya K3, Yamasaki R4, Arata T3, Shigeyasu K5, Aoki H3, Morito T4, Sanaii H6, Akagi K7, Fujiwara T5.

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Abstract

BACKGROUND:

Lynch syndrome (LS) is a predominantly inherited syndrome caused by a pathological germline mutation in one of the mismatch repair (MMR) genes. Whether breast cancer (BC) is one of the LS-associated tumors is controversial. The aim of this retrospective cohort study was to evaluate the clinical features of BC in Japanese patients with LS.

METHODS:

Of 38 mutation carriers, 4 females with BC were examined in this study.

RESULTS:

Two of the four patients had multiple BC. Their median age at the diagnosis of BC was 63 (range, 47-84) years. The TNM (6th revision) stages of the six BCs were as follows: stage I, 33% (2/6); stage IIA, 50% (3/6); and stage IIB, 17% (1/6). Histological examination revealed four scirrhous, one papillotubular, and one medullary carcinoma. The positive ratios for estrogen receptor (ER), progesterone receptor (PgR), and human epidermal growth receptor 2 (HER2) were 83.3% (5/6), 83.3% (5/6), and 16.7% (1/6), respectively. Two of the three specimens showed MSI-H and one showed MSS. These MSI-H BCs had tumor-infiltrating lymphocytes. Two of the three specimens showed an absence of MLH1 and PMS2 proteins on immunohistochemistry. The cumulative risks for a person with LS to develop BC were 4.35% at the age of 50 years, 8.70% at 60 years, and 21.5% at 70 years.