Human papilloma virus is associated with breast cancer

Abstract

Background: There is increasing evidence that high-risk human papilloma virus (HPV) is involved in cancers in addition to cervical cancer. For example, it is generally accepted that HPV has a role in a significant proportion of head and neck tumours, and it has long been hypothesised that hormone dependent oncogenic viruses, such as HPV may have causal roles in some human breast cancers. A number of reports have identified HPV DNA in breast tissue and breast cancer specimens, but these rely on standard polymerase chain reaction (PCR), which is criticised for its propensity for contamination.

Methods: We have used two different technologies, in situ and standard PCR (with sequencing), and histology based on light microscopy.

Results: We unambiguously demonstrate the presence of high-risk HPV in the cells of breast cancer specimens and breast cancer cell lines. In addition, we also show that the oncogenic characteristics of HPV associated breast cancer are very similar to HPV-associated cervical cancer. Specifically, that putative koilocytes are present in some HPV associated breast cancers.

Interpretation: The above observations indicate a likely causal role for high-risk HPV in human breast cancer and offer the possibility of primary prevention of some breast cancers by vaccination against HPV.

Figure 1

Human papilloma virus (HPV) in situ polymerase chain reaction (PCR) of breast cancer cell lines. (A–C) Cell line MBA-MB-175V11, (D–F) cell lines BR-SK3 and (G–I) cell lines HeLa (HPV-18 containing cervical cancer cell line: positive control). (A, D and G) In situ PCR with HPV E6 primers. (B, E and H) In situ PCR with HPV L1 primers. (C, F and I) No primer (negative) in situ PCR control.

Figure 2

Polymerase chain reaction (PCR) product nucleotide sequences of human papilloma virus (HPV)-positive patient samples and breast cancer cell lines. Four HPV-positive breast cancer samples were identified in Figure 4 below (specimens 2, 4, 5 and 6) and two breast cancer cell lines (SK-BR3 and MDA-MB-175) were identified as HPV type 18, whereas one breast cancer specimen (specimen 7) was identified as HPV type 16. Minor sequence variations were observed in three samples (specimens 2, 4 and 6) and in both cell lines (SK-BR and MDA-MB-175) when matched against reference sequence HPV-18 positive HeLa. There is no sequence variation in specimen 7 when matched against HPV-type 16 genome (accession FJ006723).

Figure 3

Human papilloma virus (HPV) screen of patient samples using MY and GP primers. Lane M is the Puc/Hinf ladder marker. Lanes 1–7 are patient samples (breast cancer specimens 1–7). Lane 8 is HeLa DNA as the positive control. Lanes 9–11 are negative controls (water in place of DNA in reaction). Lanes 2 (specimen 2), 4 (specimen 4), 5 (specimen 5), 6 (specimen 6) and 7 (specimen 7) show positive bands of 140 bp. Both samples in lanes 1 (specimen 1) and 3 (specimen 3) are negative for HPV.

Figure 4

Human papilloma virus (HPV) in cancer cells of ductal carcinoma in situ breast cancer demonstrated by in situ polymerase chain reaction (PCR) (same specimen in all panels). (A and B) No primer in situ PCR control ( × 20 and × 40 objective, respectively), (C and D) HPV L1 primer in situ PCR ( × 20 and × 40 objective, respectively), Dark purple stain in panels A–D indicated amplification of HPV L1 sequences by in situ PCR. (E and F) Haematoxylin and eosin stain ( × 20, × 40 objective, respectively). The appearance of koilocytes in the HPV-18 containing cells shown in panel F (selected koilocytes shown by arrows) is indicated by the clearing of the cytoplasm and condensed, hyperchromatic nuclei.